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Computer-printed labels for efficient processing of clinical specimens
Comput. Bid. Med.
Pergamon Press 1973. Vol. 3, pp. 325-336.
Printed in Great Britain.
Computer-Printed Labels for Efficient Processing of Clinical Specimens SAMUEL RAYMOND Data Processing Division, William Pepper Laboratory, Hospital of the University of Pennsylvania, Philadelphia,
Department Pennsylvania
of Pathology, 19104, U.S.A.
(Received 16 September 1971 and in revised form 30 May 1972)
Abstract-Computer-printed labels are useful in laboratory collection of clinical specimens to provide: (I) control of the collection; (2) verification of input request; (3) reporting of non-collected specimens; (4) intra-laboratory routing of specimens; (5) reduction in input errors; (6) improvement in reporting speed; (7) overall reduction of laboratory costs. Information processing Laboratory computer Clinical laboratory Input verification Laboratory costs Specimen labels Work flow
Specimen collection
INTRODUCTION THE PEPPER LABORATORY (the
clinical laboratory in the Hospital of the University of Pennsylvania) uses computer-printed labels in the collection and processing of blood specimens for chemistry, hematology, endocrinology, serology and blood-bank. These labels are used in conjunction with a computer-based data processing system for input, control, and reporting of work in these divisions of the laboratory. The data processing system, which has been described in detail and intensively analyzed in previous papers from this laboratory, has been operating successfully for several years. The label system to be described here has contributed significantly to the economy and reliabiIity of the system as a whole, and illustrates clearly the fundamental principles of medical data processing which form the basis for the design of our system.
THE
PROBLEM
The laboratory staff has the responsibility for collecting blood specimens from patients in the hospital covering the early morning scheduled laboratory requests. Unscheduled requests, including stat and opportune tests, come to the laboratory with request and specimen together, but the schedule requests for blood tests are delivered to us without the specimen. These requests, which comprise nearly half of the total number of requests processed each day, formerly arrived in the laboratory at about 7 a.m. Since it took one C.B.M. 3/3-K
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SAMUEL RAYMOND
and one-half hours for the laboratory’s venipuncture team to collect these specimens, the laboratory staff received a peak load of specimens at 8.30 a.m. which had to be accessioned, centrifuged, and otherwise prepared for analysis each morning just at the time when the staff was most involved in start-up procedures for the day’s work. This peaking in the flow of work led to inefficiency, error, and delay in the daily work. The problem was to reschedule the work at a more convenient time or to distribute it over a more efficient time interval. This problem was analyzed in two parts: (1) what is the reason for the peak concentration of laboratory tests in the early morning; and (2) can procedures be revised to distribute the work over a more acceptable time interval? (1) The peak concentration is generated by the system of clinical management followed in our hospital, which is similar to the practice in other teaching hospitals. Although the physician may, and frequently does, order stat or other opportune laboratory work at any hour of the day or night as it becomes necessary to answer the clinical problems of his patient, he schedules many of the laboratory tests for performance early the following morning, when the patient is presumably in the fasting-basal state. This makes the laboratory results easier to interpret, as they are more directly comparable from day to day and from one patient to another. It then becomes convenient, and significantly more efficient, to schedule other tests, for which the fasting-basal state is not essential, at the same time. The concentration of tests in early morning is further increased by the usual timing of rounds : the treatment rounds occur in the morning, while the service rounds-during which laboratory work is planned-occur in the afternoon, after the morning laboratory results become available. Significant work processing efficiency could be planned if this peak load were redistributed over a full workshift. The result of these factors is that more than half of inpatient laboratory tests become work which is scheduled for early morning blood specimen collection. (2) To redistribute this peak load, we must look in some detail at the current operating procedures. Although a considerable amount of analysis and redesign could profitably be applied to the initial phases of the process, from the decision by the physician to the arrival of the request in the laboratory, this area initially seemed to be clearly outside our assigned responsibility and authority. The operation began, as far as we were concerned, when the laboratory requests from all the inpatient locations were brought together in the laboratory at 7 a.m. When we looked into the matter, however, we found, as suggested by the analysis given above, that the laboratory requests were in fact most often ready for transmittal to the laboratory as early as 7 p.m. the night before. Thus, without disturbing the system of clinical practice in any way or changing operating procedures outside the laboratory to any serious degree, we could gain a lead time of nearly 12 hr in processing these laboratory requests by picking them up as soon as they were ready, rather than waiting for delivery to the laboratory. The availability of this lead time may be used to reduce the peak load on the laboratory technical staff. This can be done, by shifting the data processing part of the operation back into the lead time interval. Analysis of the laboratory processing of specimens had already demonstrated that from one-third to one-half of the time-consuming work was intrinisically data processing rather than laboratory processing in the stricter sense. By separating the data processing from the laboratory technical work, we expected to perform each more efficiently and at a more efficient time schedule. In order to see how this is possible, it is necessary to consider in detail the procedures used for the collection and processing of specimens.
Computer-printed labels for efficient processing
FORMER
SCHEDULED
327
PROCESSING
An approximate flow-chart of the manual operation is given in Fig. 1, but the procedures were frequently varied to meet exigent circumstances as determined by the operating technicians. Responsibility for specimen collection is assigned to the venipuncture team, which is made up of personnel taken in rotation from the laboratory technical staff. The venipuncture team consists of 12-15 members assigned each day to process the 2OQ-400 requests in this category. These requests are submitted, like the other laboratory requests, on 3-part carbon-interleaved forms, of which there are some 15-20 variants covering the various divisions of the laboratory and the various groups of tests within each division. The forms carry patient identification data, usually imprinted from the patient’s charge plate, and indication of the tests required, either by check marks of listed tests or by writing out the name of the test. Errors and omissions in the patient data are frequent, as they are also on the other laboratory requests which are non-scheduled. Consequently, detailed validation procedures must be applied by the laboratory before these requests can be used as the basis of a complete and reliable laboratory report. This work is essentially of a data processing nature and can clearly be separated from the technical performance of the test itself. Our data processing procedures have been described in other papers from this laboratory.
FIG. 1. Scheduled specimens collection-manual
system.
One of the most frequent errors the patient data occurs in the patient location. Since the average patient in this 900-bed hospital is transferred at least once, the patient charge plate, which carries the patient’s location within the hospital, is frequently out-of-date. Often enough, the charge plate is not used, with the result that the venipuncture team must interpret obscure handwritten indications. These and other data processing problems could
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have been cleared up by having some member of the venipuncture team preprocess the request forms as they accumulated overnight, but in the absence of suitable data processing tools and facilities, specifically an accurate and up-to-the-minute hospital census list and an efficient means for searching it, there was no incentive to carry out this pre-processing. Consequently, the practice was to allow the entire batch of scheduled requests to accumulate until the venipuncture team came together in the early morning. This event occurred daily at about 7 a.m. Their first task was to separate the requests into groups according to the scheduled collection rounds. This was a rather complex procedure, involving a great deal of crossmatching of forms from various divisions of the laboratory; the personnel from each division preferred to collect their own samples. This meant that several team members might visit the same hospital location* and even the same patient, although an effort was made to have ail the specimens on any one patient collected at one time so that the patient would be stuck only once. Mistakes in grouping the requests were known to occur, when multiple requests on one patient were addressed to different divisions (chemistry, hematology, etc.) of the laboratory, but the general impression was that the system was working reasonably well. After grouping the requests into collection routes, each individual team member sorted her requests into sequence for convenience in traversing her route. Then, taking the original requests with her, along with the blood drawing equipment, she visited each patient on her list in turn, according to the location shown on the request. On arriving at the patient’s specified location, she collected the required specimens, first estimating the volume of blood to be drawn and selecting the proper specimen tubes from the test indications marked on the request slips. After obtaining the specimens, she identified them by wrapping the test request form around the tubes and attaching it with a paper clip. In about 10 per cent of the cases (this figure was not recognized to be so high until after the revised label procedure was put into operation) the technician was not able to obtain the specimen. The reasons for this were various, some correctable and some not. In many of these cases, the patient location was wrong, so that the technician had to make a detour to find the patient, if she could learn the new location. In some cases the patient was temporarily absent, having been taken away for an X-ray, for example. In other cases, the patient may have been discharged, or may have died. Sometimes the patient might already have been stuck by another blood collector: for this or other reasons the patient might refuse to allow the technician to draw the required specimen. Occasionally, the technician may have had difficulty in completing the technical operation of finding and piercing a vein. Statistics on all these contingencies would be valuable in controlling and improving the overall procedure. Nevertheless, in all cases of failure to obtain the specimen, the practice was to leave the request forms for the unfilled requests at the nursing station, without making any record of the action. In theory, these slips would be passed on to the requesting physician, who would then decide to collect and forward the specimen himself, to resubmit the request again for the next day, or to cancel the request outright. In fact, the uncollected requests were frequently overlooked until the physician failed to get an expected laboratory report, and then they generated controversy between the physician and the laboratory staff as to the responsibility of each for the failure. * Not a negligible factor: our hospital covers two city blocks and up to ten floors.
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The entire operation of sorting the slips and collecting the specimens required about 2 hr, for the entire venipuncture team of 12-15 technicians, starting at 7 a.m. By the time the technicians returned to the laboratory with their collected specimens, a good many of the data processing problems such as patient misidentification had disappeared, unrecognized and unrecorded, by in effect discarding them. This practice carried no possibility of improvement within itself, and was unacceptable in terms of formal laboratory policy, which requires a complete and reliable response to every request for patient service. The magnitude of the problem was, indeed, not known to the laboratory director, although an indication of it was to be found in the number of telephone calls received in the laboratory each day. Within the batch of specimens brought back to the laboratory, the technician could ipso,fucto assume that the laboratory request form was correct with respect to patient name and location but not necessarily identification numbers. Nevertheless, there still remained a formidable task of accessioning the specimens and creating the necessary laboratory records, including daily log, spin sheets, and worksheets, at a time of day when a great deal of other work was also required in starting up the day’s procedures in the laboratory. These additional procedures formerly occupied several hours of attention from nearly all the laboratory staff, mostly interspersed among more technical duties also claiming their attention, with the result that it was frequently as late as 11 a.m. before the analytical work itself really commenced. At the time that the change described below was introduced in the specimen collection procedure, the laboratory was already using our computer-based accessioning procedure with some improvement in efficiency over the previous purely manual methods. (Details of this part of our data processing system have been presented in another paper.) It still required, however, a further hour of work before the specimens were ready for the definitive laboratory procedures. The expected time scale, then, prior to the introduction of the revised label procedure, was that laboratory testing began at about 10 a.m. In the context of this present description, the further details of the result recording and report generation can be left to another place and we can now turn to a description of our revised procedure. REVISED
SPECIMEN
PROCESSING
Figure 2 presents a flow-chart of the revised procedure for specimen collecting and processing. Although this procedure appears to be more complicated than the manual procedure which it replaces, most of the steps as charted are carried out automatically and with complete and unfailing accuracy by the computer. The procedure with respect to the actual laboratory operations is clearly simpler and more efficient. We emphasize as one of our primary objectives, the elimination of data processing errors, whether caused by our own mistakes or by erroneous data furnished to us by others, and the institution of complete control of every individual request received in the laboratory. We realize that other systems, apparently successful in operation, reject test requests which do not meet prescribed and usually quite strict data processing standards. Such a policy shifts to others outside the laboratory the responsibility for validating laboratory input. We are satisfied that taking this responsibility upon ourselves fully meets our professional standards, provides better service, and contributes real savings to the total hospital budget. In addition, we have demanded that the system must provide complete back-up procedures both during the introduction period and permanently thereafter, for use in case of
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SAMUELRAYMOND
ACCESSION SENT
TO
LAB
TECHNICIAN
COLLECTIONS AND CONTROL LASELS
TO COMPVTER
CORRECT TO
THE
COMPUTER
NOTE: SEE NOTE TO FIGURE 1.
FIG. 2. Scheduled specimens collection-computer
any breakdown
in the computer.
This back-up,
system.
in our system, takes the form of having the
computer output (e.g. labels, worksheets, master accession list) carry all of the information which was contained on the original laboratory request slip, and making use of this output in a way which duplicates in all essential steps the procedures used in the former manual system. Under these conditions, the laboratory staff can immediately revert to manual methods in case of any breakdown in either the computer equipment or the operating procedures associated with it. Although this feature has been invoked no more than once in two or three months, and each time for not longer than six hours, it is nevertheless a safety precaution of great value in making the system acceptable to the laboratory staff. The stringency of these back-up requirements may suggest considerable doubt whether the computer-based system offers any significant advantages over the manual system, or whether it merely superimposes an expensive computer operation on top of a manual system which, whatever its defects, was visibly operating and apparently operating well. The answer to this question will be given in a later section, but we may say here that the revised system, from its very first day of operation, demonstrated such significant advantages that no one in the laboratory would willingly give up the revised system. Following the flow-diagram of Fig. 2, the initial procedures involved in setting up the laboratory request remain the same. Special arrangements are made, however, to have a member of the computer staff pick up the completed laboratory request forms at intervals
FIG. 3. Computer-printed
labels. A-Control
label.
CBM facing page 330
Computer-printedlabels for efficientprocessing
331
during the evening and night shifts (7 p.m.-6 a.m.). In addition to their other assigned duties, the computer operators process and accession the laboratory requests as they come in during the night. This operation does not in fact add anything to the workload but merely a shift in its work schedule, since the amount of work involved is exactly the same as that required to process and access the same laboratory requests if they arrived in the regular way during the day. The work is merely transferred from a particularly busy period (8-10 a.m.) and distributed over a comparatively quiescent period (7 p.m.-6 a.m.). During this period, the test requests are checked and verified, and then entered into the accession file, using principles and procedures which we have described elsewhere and which are essentially the same as those which continue in operation for requests received during the day. Before the venipuncture team assembles at 7 a.m., the operator executes a computer program which prints a set of collection and control labels in the collection operation. (The computer also prints other sets of labels which will be used as described below in the further processing of specimens in the laboratory.) The labels are printed on pressuresensitive label blanks which are mounted on a continuous backing strip for passage through the computer’s line printer (see Fig. 3). With this backing strip it is easy to handle a batch of labels as a work list. Before printing these labels, the computer arranges them in a convenient routing sequence for blood collection. All the labels pertaining to an individual patient are grouped together, so that there is no question of having a patient visited by several members of the venipuncture team. Thus all specimens required are collected on one venipuncture. It is a special feature of our operation that each label includes complete patient identification data from the original request, and also all other pertinent information from the request. This information includes the patient name, six-digit hospital number, room or bed number, a laboratory accession number assigned for the day, the date, the laboratory destination of the specimen, and an input comment code. A mere serial number, which would have to be correlated at some later time in the processing of the specimen with other essential information, is not considered acceptable. If necessary, up to 25 characters of alphanumeric comment can be printed on the label, and for ultimate flexibility the comment could be extended from one label to another, although this has never proved to be necessary in practice. The label also carries a code designating the type of specimen tube to be used, and fourletter mnemonics for the tests required. When multiple tests are required on one patient, the computer is programmed to divide them appropriately into groups corresponding to the subdivisions of laboratory processing areas. It then computes the volume of blood to be collected, assigns the required number of appropriate tube types, and generates a separate label for each tube. This relieves the technician of the necessity of carrying out these computations at the bedside, and encourages her to draw an adequate specimen for all the tests required. Thus, when the specimens are returned to the laboratory, all the enzyme specimens, for example, can be immediately separated from the other types of tests and distributed to the enzyme area of the laboratory for processing. The technician, in the usual case, is required to collect one tube of blood for each label printed. Although this appears to reduce the collection process to a mere mechanical operation of matching label with patient and filling the tube, we emphasize always that we rely on the experience and skill of the technician to solve any of the unforeseen problems or circumstances which may arise in the medical environment. By taking care of all the merely
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SAMUELRAYMOND
clerical work, by computer, we expect to free the technician’s attention for the technical problems as they occur. In addition to the specimen labels, the computer prints a single control label for each patient, which appears on the backing strip as a header to the group of labels pertaining to a given patient. This label includes all of the constant patient identity data as before, but in place of the test indicators it provides space to check off any of the common reasons for failing to obtain the specimens called for, such as: absent; discharged; refused; no veins; and other. The technicians are explicitly instructed never to remove the control labels from the backing sheet, and to return the backing sheet intact, since the control procedure depends on getting a complete return of all control labels. In every case, the technician marks the control label to indicate the result of the collection attempt: “OK” if the required specimens are obtained, or the specific reason if they are not. A special case, when specimens are not obtained, is indicated when the patient has been discharged or has died: in such cases all the specimen labels are returned to the computer along with the control label. In other cases of failure to obtain specimen, the specimen labels are removed from the backing, affixed to appropriate blank request forms, and left at the nursing station for the attention of the physician. (The physician also receives, somewhat later, a computer-generated report explicitly noting that the specimens were not obtained.) Since the label bears all the necessary information to reproduce the request, including the names of the tests requested, these request forms with labels attached enable the physician to repeat the request or to draw and forward the specimen himself as he chooses. On the other hand, if the specimens are successfully obtained, the technician draws one tube of blood for each label, guided by the tube color specified on the label, and affixes the label to the tube. The pressure-sensitive labels peel easily from the backing sheet and adhere permanently to the specimen tubes when pressed on to the glass surface. They are of a size (1 x 24 in.) convenient to fit longitudinally on a standard vacuum blood tube. Technicians report that the printed labels are easier to interpret than the original request forms, are easier to handle and keep in order, and are attached more quickly to the tubes than the request forms they replace, and, because of the validation procedures already executed by the computer staff, there are virtually no errors in patient location to deal with. In all of this processing, the original request forms never leave the custody of the laboratory, specifically the computer staff. They remain available for reference or confirmation in any of the unforeseen and unforeseeable questions which may arise. When the laboratory assumes, as ours does, the full responsibility for the completeness and reliability of both the laboratory request and the report generated from it, the preservation of the original request form is a necessary, and also an adequate precaution. When the technician returns to the laboratory with the specimens she has collected, she deposits the labeled tubes at the accession area and brings the control label list to the computer staff. (We consider it necessary to have the computer staff directly accessible to the laboratory personnel.) She informs the computer operator of any special problems encountered. The operator analyzes her information and the control label list to determine what corrections, if any, are required in the accession file, upon which depends all of the subsequent processing of the specimen. Usually there are no corrections, except for the deletion of specimens not collected. If these deletions were not made to the accession list, the specimens not collected would keep turning up as “lost” in the control lists and work-
Computer-printed
labels for efficient processing
333
sheets which are generated within the system throughout the day. This would have the effect of delaying the processing of the other specimens through the laboratory and would also delay the appearance of the completed reports for the day. While this data processing activity is going on, the blood specimens themselves are being physically processed in the accession area for further distribution to the analysis area of the laboratory. For many tests, using whole blood, no further physical processing is required, so that the specimens can be directly distributed to the analysis areas. This distribution is made much easier by the fact that the computer has grouped the tests on the specimen labels according to the subdivision in the laboratory which processes those tests together, so that in many cases all that is necessary is to deliver the labeled tube, which carries on its label all the information necessary for the analyst to proceed with the test, directly to the laboratory area concerned. Not only is there far less confusion and conflict than in the former procedure of aliquoting from a common specimen tube, but also there has been a reduction in the number of specimens reports as “quantity not sufficient”. For those tests requiring the separation of serum from the specimen, the computer has generated, on the basis of the data in its accession file, serum labels for each such specimen. The serum label lists themselves are used by the accession area as a check list of specimens which have to be centrifuged, and a complete set of labeled tubes is ready to receive the serum as the specimen tubes are removed from the centrifuge. By the time the specimens have been delivered to the analysts, the master log sheets and all necessary work sheets have been printed. Further processing, including transcription of results and generation of reports, is carried out by procedures described in other papers from this laboratory. We now turn to the results achieved by this revised procedure. RESULTS The first result of the new system appeared within an hour of its introduction, when the venipuncture team returned early and with reports of improved efficiency and convenience; the second appeared an hour later, when the laboratory reported 23 specimens missing out of an accession of 209 from the morning’s scheduled batch. These results were repeatedly confirmed in subsequent weeks. 1. Efficiency and economy of the new system These can be described in terms of (a) collection procedure, (b) accession procedure, (c) computer costs, and (d) other implications. (a) Collection procedure. As described above, the label procedure eliminates entirely the manual operations of collating and sorting the requests by the venipuncture team. The pre-accession verification of patient data reduces the number of wasted trips. The technicians report that the labels are easier and faster in use than the original request forms. The sum of all these is a saving of about 1 hr each day for the venipuncture team over the time required for the old manual procedure. This amounts to a saving of 10-l 5 technicianhours per day for the collection operation alone, depending on the size of the venipuncture team and on the variation in number of scheduled tests each day. Before this saving could be properly substantiated on a statistical basis, it was in part pre-empted by an administrative decision extending the specimen collection service to include patient areas and types of tests not previously covered. Specifically, the service was extended towards where the
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intern or resident formerly drew the blood sample. Also, a change was made in some of the hematology procedures, formerly performed using capillary blood from a finger-stick. The facility of the new blood collection procedure prompted the hematology division to revise its procedures so that all hematology procedures are now done on specimens collected by venipuncture, with a saving of over 30 man-hours a day in the hematology laboratory. In spite of the increased workload imposed by these changes, the collection procedure continues to be an hour faster overall than the old method. The time saved is passed on to the technical areas of the laboratory in the form of an earlier starting time for their analytical procedures. (b) Accession procedure. The new procedures described above have eliminated the accessioning of scheduled specimens in the laboratory. The accession process formerly required both an hour or more of time, and the attention of half the technicians in the laboratory, in order to transcribe test request information into a form suitable for entering into the system .* The elimination of this work not only makes the computer data processing specimens available to the laboratory an hour earlier than they formerly were, but also frees the laboratory staff from this data processing chore and permits them to devote their attention to start-up procedures at a critical time of day. There are two important components in this improvement: (1) the elimination of the transcription step, which is now a direct key-punching operation; and (2) the transfer of input validation procedures, which formerly were carried on under stress during the first 2 hr of the working day, to a quieter time during the night shift when they could be performed more efficiently and with more careful attention to detail. These time-savings relate to the chemistry division alone. The hematology division, which uses a different system, reports that they receive their samples 2 hr earlier than under the former system (in part this represents a change from capillary samples, which were formerly collected separately by the hematology technicians) and that consequently the twenty technicians in hematology get their work started 2 hr earlier. The other divisions of the laboratory served by the new system include endocrinology, serology, and blood bank. Because of the individual nature and relatively small numbers of specimens involved in these divisions, no specifically remarkable efforts have been reported in these areas. (c) Computer costs. The savings in personnel time derived from the label-preaccession operation can be summarized as follows: collection procedures, IO-15 man-hours; accessioning (Chemistry), 20 man-hours; and hematology, 40 man-hours; total 70-75 man-hours per day. This would not be a laudable achievement if it were obtained at the price of a corresponding increase in workload or costs in the computer division. The astonishing fact is, however, that these achievements have been obtained with virtually no increase in computer operating cost or personnel workload at all. The changes involved included, in addition to the redesign and reprogramming of the computer operation, a shift in working hours of one operator from the day shift to the night shift. The extra cost of the label stock and other consumable supplies used in the new operation amounts to a trivial sum, less than $10 per day. The actual redesign and reprogramming of the operation occupied our staff for about
* Thisprocess was itself, however, a substantial improvement
over precomputer
procedures.
Computer-printed
labels for efficient processing
335
half time over a period of two months: the capital cost of this effort can be expected to be fully recovered in less than three months. (d) Other implications. Other than the time and cost savings, we cannot assess at this time any quantitative effects either within or outside the laboratory. We have no objective evidence that the label identification of specimens, although intrinsically more secure, has actually prevented errors in specimen identification. The time saved in the laboratory by the elimination of the wax marking pencil and by the use of specimen tubes fully labeled even to level of the tests required has proved difficult to estimate. We can only say that these niceties have been welcomed by those using them.
2. Control The second major result of the label-processing procedure is the introduction of control into the scheduled-specimen collection operation. In formal terms, this operation was out of control when the original source document-the laboratory request form-was removed from the laboratory without leaving any record in the laboratory, and even further when the form was discarded on a nursing station desk with neither confirmation that this was its proper destination nor accounting made of its final disposition. This lack of control might not be a cause of serious concern if only one or two requests a day were involved, although a case can be made that even one mislaid laboratory request a day is too much, considering the cost of an extra day’s stay in the hospital for one patient; but surprisingly, as many as 10 per cent of the total number of scheduled requests were not filled, as demonstrated by the evidence of the control label processing. The fact that the control label system was needed to uncover this rate of failure is in itself an adequate justification for the necessity of an explicit control procedure. As shown elsewhere, the essence of control is to provide positive evidence that the operation is proceeding correctly; the mere absence of evidence for incorrect operation is not enough. Thus the observed fact, in the old system, that no unfilled requests were returned did not mean that there were none. An example of this principle occurred early in the introduction of the label-processing system. After the experience of the first few days showed that 10 per cent of the requests were uncollected, we noticed that fewer control labels were returned as uncollected apparently showing that the collection rate was rising toward complete collection. Further investigation showed that technicians, when unable to obtain a specimen, were now leaving the control label as well as specimen labels at the nursing station. Control of the controls was finally achieved by counting the control labels before releasing them to the venipuncture team, and by tallying with the count of returned control labels. Having demonstrated the need for and possibility of control in the collection of scheduled specimens, we now propose to use this control information to improve the rate of collection. Measures for this improvement lie outside the scope of this present paper. It is enough to point out that the label-processing system works well when only 90 per cent of the specimens are collected, and that it will work even better as we approach the 100 per cent level. Even if we attain that desired level, we would not expect to abandon the control procedures. They require only a small amount of extra effort on the operation as a whole-an effort which will certainly decrease as we approach 100 per cent-and they provide necessary and adequate safeguards against unforeseen or unauthorized changes in the operation which might allow the rate of collection to fall back to unsatisfactory levels.
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SUMMARY The label-processing system of the Pepper Laboratory covers two-fifths of the daily workload comprising the scheduled early morning blood specimens. This system, providing computer printed labels for the specimens to be drawn by laboratory personnel, saves 70 man-hours a day in technician time with virtually no increase in computer cost. It provides control data on the collection operation which is used to improve the service.
Pergamon Press 1973. Vol. 3, pp. 325-336.
Printed in Great Britain.
Computer-Printed Labels for Efficient Processing of Clinical Specimens SAMUEL RAYMOND Data Processing Division, William Pepper Laboratory, Hospital of the University of Pennsylvania, Philadelphia,
Department Pennsylvania
of Pathology, 19104, U.S.A.
(Received 16 September 1971 and in revised form 30 May 1972)
Abstract-Computer-printed labels are useful in laboratory collection of clinical specimens to provide: (I) control of the collection; (2) verification of input request; (3) reporting of non-collected specimens; (4) intra-laboratory routing of specimens; (5) reduction in input errors; (6) improvement in reporting speed; (7) overall reduction of laboratory costs. Information processing Laboratory computer Clinical laboratory Input verification Laboratory costs Specimen labels Work flow
Specimen collection
INTRODUCTION THE PEPPER LABORATORY (the
clinical laboratory in the Hospital of the University of Pennsylvania) uses computer-printed labels in the collection and processing of blood specimens for chemistry, hematology, endocrinology, serology and blood-bank. These labels are used in conjunction with a computer-based data processing system for input, control, and reporting of work in these divisions of the laboratory. The data processing system, which has been described in detail and intensively analyzed in previous papers from this laboratory, has been operating successfully for several years. The label system to be described here has contributed significantly to the economy and reliabiIity of the system as a whole, and illustrates clearly the fundamental principles of medical data processing which form the basis for the design of our system.
THE
PROBLEM
The laboratory staff has the responsibility for collecting blood specimens from patients in the hospital covering the early morning scheduled laboratory requests. Unscheduled requests, including stat and opportune tests, come to the laboratory with request and specimen together, but the schedule requests for blood tests are delivered to us without the specimen. These requests, which comprise nearly half of the total number of requests processed each day, formerly arrived in the laboratory at about 7 a.m. Since it took one C.B.M. 3/3-K
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and one-half hours for the laboratory’s venipuncture team to collect these specimens, the laboratory staff received a peak load of specimens at 8.30 a.m. which had to be accessioned, centrifuged, and otherwise prepared for analysis each morning just at the time when the staff was most involved in start-up procedures for the day’s work. This peaking in the flow of work led to inefficiency, error, and delay in the daily work. The problem was to reschedule the work at a more convenient time or to distribute it over a more efficient time interval. This problem was analyzed in two parts: (1) what is the reason for the peak concentration of laboratory tests in the early morning; and (2) can procedures be revised to distribute the work over a more acceptable time interval? (1) The peak concentration is generated by the system of clinical management followed in our hospital, which is similar to the practice in other teaching hospitals. Although the physician may, and frequently does, order stat or other opportune laboratory work at any hour of the day or night as it becomes necessary to answer the clinical problems of his patient, he schedules many of the laboratory tests for performance early the following morning, when the patient is presumably in the fasting-basal state. This makes the laboratory results easier to interpret, as they are more directly comparable from day to day and from one patient to another. It then becomes convenient, and significantly more efficient, to schedule other tests, for which the fasting-basal state is not essential, at the same time. The concentration of tests in early morning is further increased by the usual timing of rounds : the treatment rounds occur in the morning, while the service rounds-during which laboratory work is planned-occur in the afternoon, after the morning laboratory results become available. Significant work processing efficiency could be planned if this peak load were redistributed over a full workshift. The result of these factors is that more than half of inpatient laboratory tests become work which is scheduled for early morning blood specimen collection. (2) To redistribute this peak load, we must look in some detail at the current operating procedures. Although a considerable amount of analysis and redesign could profitably be applied to the initial phases of the process, from the decision by the physician to the arrival of the request in the laboratory, this area initially seemed to be clearly outside our assigned responsibility and authority. The operation began, as far as we were concerned, when the laboratory requests from all the inpatient locations were brought together in the laboratory at 7 a.m. When we looked into the matter, however, we found, as suggested by the analysis given above, that the laboratory requests were in fact most often ready for transmittal to the laboratory as early as 7 p.m. the night before. Thus, without disturbing the system of clinical practice in any way or changing operating procedures outside the laboratory to any serious degree, we could gain a lead time of nearly 12 hr in processing these laboratory requests by picking them up as soon as they were ready, rather than waiting for delivery to the laboratory. The availability of this lead time may be used to reduce the peak load on the laboratory technical staff. This can be done, by shifting the data processing part of the operation back into the lead time interval. Analysis of the laboratory processing of specimens had already demonstrated that from one-third to one-half of the time-consuming work was intrinisically data processing rather than laboratory processing in the stricter sense. By separating the data processing from the laboratory technical work, we expected to perform each more efficiently and at a more efficient time schedule. In order to see how this is possible, it is necessary to consider in detail the procedures used for the collection and processing of specimens.
Computer-printed labels for efficient processing
FORMER
SCHEDULED
327
PROCESSING
An approximate flow-chart of the manual operation is given in Fig. 1, but the procedures were frequently varied to meet exigent circumstances as determined by the operating technicians. Responsibility for specimen collection is assigned to the venipuncture team, which is made up of personnel taken in rotation from the laboratory technical staff. The venipuncture team consists of 12-15 members assigned each day to process the 2OQ-400 requests in this category. These requests are submitted, like the other laboratory requests, on 3-part carbon-interleaved forms, of which there are some 15-20 variants covering the various divisions of the laboratory and the various groups of tests within each division. The forms carry patient identification data, usually imprinted from the patient’s charge plate, and indication of the tests required, either by check marks of listed tests or by writing out the name of the test. Errors and omissions in the patient data are frequent, as they are also on the other laboratory requests which are non-scheduled. Consequently, detailed validation procedures must be applied by the laboratory before these requests can be used as the basis of a complete and reliable laboratory report. This work is essentially of a data processing nature and can clearly be separated from the technical performance of the test itself. Our data processing procedures have been described in other papers from this laboratory.
FIG. 1. Scheduled specimens collection-manual
system.
One of the most frequent errors the patient data occurs in the patient location. Since the average patient in this 900-bed hospital is transferred at least once, the patient charge plate, which carries the patient’s location within the hospital, is frequently out-of-date. Often enough, the charge plate is not used, with the result that the venipuncture team must interpret obscure handwritten indications. These and other data processing problems could
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have been cleared up by having some member of the venipuncture team preprocess the request forms as they accumulated overnight, but in the absence of suitable data processing tools and facilities, specifically an accurate and up-to-the-minute hospital census list and an efficient means for searching it, there was no incentive to carry out this pre-processing. Consequently, the practice was to allow the entire batch of scheduled requests to accumulate until the venipuncture team came together in the early morning. This event occurred daily at about 7 a.m. Their first task was to separate the requests into groups according to the scheduled collection rounds. This was a rather complex procedure, involving a great deal of crossmatching of forms from various divisions of the laboratory; the personnel from each division preferred to collect their own samples. This meant that several team members might visit the same hospital location* and even the same patient, although an effort was made to have ail the specimens on any one patient collected at one time so that the patient would be stuck only once. Mistakes in grouping the requests were known to occur, when multiple requests on one patient were addressed to different divisions (chemistry, hematology, etc.) of the laboratory, but the general impression was that the system was working reasonably well. After grouping the requests into collection routes, each individual team member sorted her requests into sequence for convenience in traversing her route. Then, taking the original requests with her, along with the blood drawing equipment, she visited each patient on her list in turn, according to the location shown on the request. On arriving at the patient’s specified location, she collected the required specimens, first estimating the volume of blood to be drawn and selecting the proper specimen tubes from the test indications marked on the request slips. After obtaining the specimens, she identified them by wrapping the test request form around the tubes and attaching it with a paper clip. In about 10 per cent of the cases (this figure was not recognized to be so high until after the revised label procedure was put into operation) the technician was not able to obtain the specimen. The reasons for this were various, some correctable and some not. In many of these cases, the patient location was wrong, so that the technician had to make a detour to find the patient, if she could learn the new location. In some cases the patient was temporarily absent, having been taken away for an X-ray, for example. In other cases, the patient may have been discharged, or may have died. Sometimes the patient might already have been stuck by another blood collector: for this or other reasons the patient might refuse to allow the technician to draw the required specimen. Occasionally, the technician may have had difficulty in completing the technical operation of finding and piercing a vein. Statistics on all these contingencies would be valuable in controlling and improving the overall procedure. Nevertheless, in all cases of failure to obtain the specimen, the practice was to leave the request forms for the unfilled requests at the nursing station, without making any record of the action. In theory, these slips would be passed on to the requesting physician, who would then decide to collect and forward the specimen himself, to resubmit the request again for the next day, or to cancel the request outright. In fact, the uncollected requests were frequently overlooked until the physician failed to get an expected laboratory report, and then they generated controversy between the physician and the laboratory staff as to the responsibility of each for the failure. * Not a negligible factor: our hospital covers two city blocks and up to ten floors.
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The entire operation of sorting the slips and collecting the specimens required about 2 hr, for the entire venipuncture team of 12-15 technicians, starting at 7 a.m. By the time the technicians returned to the laboratory with their collected specimens, a good many of the data processing problems such as patient misidentification had disappeared, unrecognized and unrecorded, by in effect discarding them. This practice carried no possibility of improvement within itself, and was unacceptable in terms of formal laboratory policy, which requires a complete and reliable response to every request for patient service. The magnitude of the problem was, indeed, not known to the laboratory director, although an indication of it was to be found in the number of telephone calls received in the laboratory each day. Within the batch of specimens brought back to the laboratory, the technician could ipso,fucto assume that the laboratory request form was correct with respect to patient name and location but not necessarily identification numbers. Nevertheless, there still remained a formidable task of accessioning the specimens and creating the necessary laboratory records, including daily log, spin sheets, and worksheets, at a time of day when a great deal of other work was also required in starting up the day’s procedures in the laboratory. These additional procedures formerly occupied several hours of attention from nearly all the laboratory staff, mostly interspersed among more technical duties also claiming their attention, with the result that it was frequently as late as 11 a.m. before the analytical work itself really commenced. At the time that the change described below was introduced in the specimen collection procedure, the laboratory was already using our computer-based accessioning procedure with some improvement in efficiency over the previous purely manual methods. (Details of this part of our data processing system have been presented in another paper.) It still required, however, a further hour of work before the specimens were ready for the definitive laboratory procedures. The expected time scale, then, prior to the introduction of the revised label procedure, was that laboratory testing began at about 10 a.m. In the context of this present description, the further details of the result recording and report generation can be left to another place and we can now turn to a description of our revised procedure. REVISED
SPECIMEN
PROCESSING
Figure 2 presents a flow-chart of the revised procedure for specimen collecting and processing. Although this procedure appears to be more complicated than the manual procedure which it replaces, most of the steps as charted are carried out automatically and with complete and unfailing accuracy by the computer. The procedure with respect to the actual laboratory operations is clearly simpler and more efficient. We emphasize as one of our primary objectives, the elimination of data processing errors, whether caused by our own mistakes or by erroneous data furnished to us by others, and the institution of complete control of every individual request received in the laboratory. We realize that other systems, apparently successful in operation, reject test requests which do not meet prescribed and usually quite strict data processing standards. Such a policy shifts to others outside the laboratory the responsibility for validating laboratory input. We are satisfied that taking this responsibility upon ourselves fully meets our professional standards, provides better service, and contributes real savings to the total hospital budget. In addition, we have demanded that the system must provide complete back-up procedures both during the introduction period and permanently thereafter, for use in case of
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ACCESSION SENT
TO
LAB
TECHNICIAN
COLLECTIONS AND CONTROL LASELS
TO COMPVTER
CORRECT TO
THE
COMPUTER
NOTE: SEE NOTE TO FIGURE 1.
FIG. 2. Scheduled specimens collection-computer
any breakdown
in the computer.
This back-up,
system.
in our system, takes the form of having the
computer output (e.g. labels, worksheets, master accession list) carry all of the information which was contained on the original laboratory request slip, and making use of this output in a way which duplicates in all essential steps the procedures used in the former manual system. Under these conditions, the laboratory staff can immediately revert to manual methods in case of any breakdown in either the computer equipment or the operating procedures associated with it. Although this feature has been invoked no more than once in two or three months, and each time for not longer than six hours, it is nevertheless a safety precaution of great value in making the system acceptable to the laboratory staff. The stringency of these back-up requirements may suggest considerable doubt whether the computer-based system offers any significant advantages over the manual system, or whether it merely superimposes an expensive computer operation on top of a manual system which, whatever its defects, was visibly operating and apparently operating well. The answer to this question will be given in a later section, but we may say here that the revised system, from its very first day of operation, demonstrated such significant advantages that no one in the laboratory would willingly give up the revised system. Following the flow-diagram of Fig. 2, the initial procedures involved in setting up the laboratory request remain the same. Special arrangements are made, however, to have a member of the computer staff pick up the completed laboratory request forms at intervals
FIG. 3. Computer-printed
labels. A-Control
label.
CBM facing page 330
Computer-printedlabels for efficientprocessing
331
during the evening and night shifts (7 p.m.-6 a.m.). In addition to their other assigned duties, the computer operators process and accession the laboratory requests as they come in during the night. This operation does not in fact add anything to the workload but merely a shift in its work schedule, since the amount of work involved is exactly the same as that required to process and access the same laboratory requests if they arrived in the regular way during the day. The work is merely transferred from a particularly busy period (8-10 a.m.) and distributed over a comparatively quiescent period (7 p.m.-6 a.m.). During this period, the test requests are checked and verified, and then entered into the accession file, using principles and procedures which we have described elsewhere and which are essentially the same as those which continue in operation for requests received during the day. Before the venipuncture team assembles at 7 a.m., the operator executes a computer program which prints a set of collection and control labels in the collection operation. (The computer also prints other sets of labels which will be used as described below in the further processing of specimens in the laboratory.) The labels are printed on pressuresensitive label blanks which are mounted on a continuous backing strip for passage through the computer’s line printer (see Fig. 3). With this backing strip it is easy to handle a batch of labels as a work list. Before printing these labels, the computer arranges them in a convenient routing sequence for blood collection. All the labels pertaining to an individual patient are grouped together, so that there is no question of having a patient visited by several members of the venipuncture team. Thus all specimens required are collected on one venipuncture. It is a special feature of our operation that each label includes complete patient identification data from the original request, and also all other pertinent information from the request. This information includes the patient name, six-digit hospital number, room or bed number, a laboratory accession number assigned for the day, the date, the laboratory destination of the specimen, and an input comment code. A mere serial number, which would have to be correlated at some later time in the processing of the specimen with other essential information, is not considered acceptable. If necessary, up to 25 characters of alphanumeric comment can be printed on the label, and for ultimate flexibility the comment could be extended from one label to another, although this has never proved to be necessary in practice. The label also carries a code designating the type of specimen tube to be used, and fourletter mnemonics for the tests required. When multiple tests are required on one patient, the computer is programmed to divide them appropriately into groups corresponding to the subdivisions of laboratory processing areas. It then computes the volume of blood to be collected, assigns the required number of appropriate tube types, and generates a separate label for each tube. This relieves the technician of the necessity of carrying out these computations at the bedside, and encourages her to draw an adequate specimen for all the tests required. Thus, when the specimens are returned to the laboratory, all the enzyme specimens, for example, can be immediately separated from the other types of tests and distributed to the enzyme area of the laboratory for processing. The technician, in the usual case, is required to collect one tube of blood for each label printed. Although this appears to reduce the collection process to a mere mechanical operation of matching label with patient and filling the tube, we emphasize always that we rely on the experience and skill of the technician to solve any of the unforeseen problems or circumstances which may arise in the medical environment. By taking care of all the merely
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clerical work, by computer, we expect to free the technician’s attention for the technical problems as they occur. In addition to the specimen labels, the computer prints a single control label for each patient, which appears on the backing strip as a header to the group of labels pertaining to a given patient. This label includes all of the constant patient identity data as before, but in place of the test indicators it provides space to check off any of the common reasons for failing to obtain the specimens called for, such as: absent; discharged; refused; no veins; and other. The technicians are explicitly instructed never to remove the control labels from the backing sheet, and to return the backing sheet intact, since the control procedure depends on getting a complete return of all control labels. In every case, the technician marks the control label to indicate the result of the collection attempt: “OK” if the required specimens are obtained, or the specific reason if they are not. A special case, when specimens are not obtained, is indicated when the patient has been discharged or has died: in such cases all the specimen labels are returned to the computer along with the control label. In other cases of failure to obtain specimen, the specimen labels are removed from the backing, affixed to appropriate blank request forms, and left at the nursing station for the attention of the physician. (The physician also receives, somewhat later, a computer-generated report explicitly noting that the specimens were not obtained.) Since the label bears all the necessary information to reproduce the request, including the names of the tests requested, these request forms with labels attached enable the physician to repeat the request or to draw and forward the specimen himself as he chooses. On the other hand, if the specimens are successfully obtained, the technician draws one tube of blood for each label, guided by the tube color specified on the label, and affixes the label to the tube. The pressure-sensitive labels peel easily from the backing sheet and adhere permanently to the specimen tubes when pressed on to the glass surface. They are of a size (1 x 24 in.) convenient to fit longitudinally on a standard vacuum blood tube. Technicians report that the printed labels are easier to interpret than the original request forms, are easier to handle and keep in order, and are attached more quickly to the tubes than the request forms they replace, and, because of the validation procedures already executed by the computer staff, there are virtually no errors in patient location to deal with. In all of this processing, the original request forms never leave the custody of the laboratory, specifically the computer staff. They remain available for reference or confirmation in any of the unforeseen and unforeseeable questions which may arise. When the laboratory assumes, as ours does, the full responsibility for the completeness and reliability of both the laboratory request and the report generated from it, the preservation of the original request form is a necessary, and also an adequate precaution. When the technician returns to the laboratory with the specimens she has collected, she deposits the labeled tubes at the accession area and brings the control label list to the computer staff. (We consider it necessary to have the computer staff directly accessible to the laboratory personnel.) She informs the computer operator of any special problems encountered. The operator analyzes her information and the control label list to determine what corrections, if any, are required in the accession file, upon which depends all of the subsequent processing of the specimen. Usually there are no corrections, except for the deletion of specimens not collected. If these deletions were not made to the accession list, the specimens not collected would keep turning up as “lost” in the control lists and work-
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sheets which are generated within the system throughout the day. This would have the effect of delaying the processing of the other specimens through the laboratory and would also delay the appearance of the completed reports for the day. While this data processing activity is going on, the blood specimens themselves are being physically processed in the accession area for further distribution to the analysis area of the laboratory. For many tests, using whole blood, no further physical processing is required, so that the specimens can be directly distributed to the analysis areas. This distribution is made much easier by the fact that the computer has grouped the tests on the specimen labels according to the subdivision in the laboratory which processes those tests together, so that in many cases all that is necessary is to deliver the labeled tube, which carries on its label all the information necessary for the analyst to proceed with the test, directly to the laboratory area concerned. Not only is there far less confusion and conflict than in the former procedure of aliquoting from a common specimen tube, but also there has been a reduction in the number of specimens reports as “quantity not sufficient”. For those tests requiring the separation of serum from the specimen, the computer has generated, on the basis of the data in its accession file, serum labels for each such specimen. The serum label lists themselves are used by the accession area as a check list of specimens which have to be centrifuged, and a complete set of labeled tubes is ready to receive the serum as the specimen tubes are removed from the centrifuge. By the time the specimens have been delivered to the analysts, the master log sheets and all necessary work sheets have been printed. Further processing, including transcription of results and generation of reports, is carried out by procedures described in other papers from this laboratory. We now turn to the results achieved by this revised procedure. RESULTS The first result of the new system appeared within an hour of its introduction, when the venipuncture team returned early and with reports of improved efficiency and convenience; the second appeared an hour later, when the laboratory reported 23 specimens missing out of an accession of 209 from the morning’s scheduled batch. These results were repeatedly confirmed in subsequent weeks. 1. Efficiency and economy of the new system These can be described in terms of (a) collection procedure, (b) accession procedure, (c) computer costs, and (d) other implications. (a) Collection procedure. As described above, the label procedure eliminates entirely the manual operations of collating and sorting the requests by the venipuncture team. The pre-accession verification of patient data reduces the number of wasted trips. The technicians report that the labels are easier and faster in use than the original request forms. The sum of all these is a saving of about 1 hr each day for the venipuncture team over the time required for the old manual procedure. This amounts to a saving of 10-l 5 technicianhours per day for the collection operation alone, depending on the size of the venipuncture team and on the variation in number of scheduled tests each day. Before this saving could be properly substantiated on a statistical basis, it was in part pre-empted by an administrative decision extending the specimen collection service to include patient areas and types of tests not previously covered. Specifically, the service was extended towards where the
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intern or resident formerly drew the blood sample. Also, a change was made in some of the hematology procedures, formerly performed using capillary blood from a finger-stick. The facility of the new blood collection procedure prompted the hematology division to revise its procedures so that all hematology procedures are now done on specimens collected by venipuncture, with a saving of over 30 man-hours a day in the hematology laboratory. In spite of the increased workload imposed by these changes, the collection procedure continues to be an hour faster overall than the old method. The time saved is passed on to the technical areas of the laboratory in the form of an earlier starting time for their analytical procedures. (b) Accession procedure. The new procedures described above have eliminated the accessioning of scheduled specimens in the laboratory. The accession process formerly required both an hour or more of time, and the attention of half the technicians in the laboratory, in order to transcribe test request information into a form suitable for entering into the system .* The elimination of this work not only makes the computer data processing specimens available to the laboratory an hour earlier than they formerly were, but also frees the laboratory staff from this data processing chore and permits them to devote their attention to start-up procedures at a critical time of day. There are two important components in this improvement: (1) the elimination of the transcription step, which is now a direct key-punching operation; and (2) the transfer of input validation procedures, which formerly were carried on under stress during the first 2 hr of the working day, to a quieter time during the night shift when they could be performed more efficiently and with more careful attention to detail. These time-savings relate to the chemistry division alone. The hematology division, which uses a different system, reports that they receive their samples 2 hr earlier than under the former system (in part this represents a change from capillary samples, which were formerly collected separately by the hematology technicians) and that consequently the twenty technicians in hematology get their work started 2 hr earlier. The other divisions of the laboratory served by the new system include endocrinology, serology, and blood bank. Because of the individual nature and relatively small numbers of specimens involved in these divisions, no specifically remarkable efforts have been reported in these areas. (c) Computer costs. The savings in personnel time derived from the label-preaccession operation can be summarized as follows: collection procedures, IO-15 man-hours; accessioning (Chemistry), 20 man-hours; and hematology, 40 man-hours; total 70-75 man-hours per day. This would not be a laudable achievement if it were obtained at the price of a corresponding increase in workload or costs in the computer division. The astonishing fact is, however, that these achievements have been obtained with virtually no increase in computer operating cost or personnel workload at all. The changes involved included, in addition to the redesign and reprogramming of the computer operation, a shift in working hours of one operator from the day shift to the night shift. The extra cost of the label stock and other consumable supplies used in the new operation amounts to a trivial sum, less than $10 per day. The actual redesign and reprogramming of the operation occupied our staff for about
* Thisprocess was itself, however, a substantial improvement
over precomputer
procedures.
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half time over a period of two months: the capital cost of this effort can be expected to be fully recovered in less than three months. (d) Other implications. Other than the time and cost savings, we cannot assess at this time any quantitative effects either within or outside the laboratory. We have no objective evidence that the label identification of specimens, although intrinsically more secure, has actually prevented errors in specimen identification. The time saved in the laboratory by the elimination of the wax marking pencil and by the use of specimen tubes fully labeled even to level of the tests required has proved difficult to estimate. We can only say that these niceties have been welcomed by those using them.
2. Control The second major result of the label-processing procedure is the introduction of control into the scheduled-specimen collection operation. In formal terms, this operation was out of control when the original source document-the laboratory request form-was removed from the laboratory without leaving any record in the laboratory, and even further when the form was discarded on a nursing station desk with neither confirmation that this was its proper destination nor accounting made of its final disposition. This lack of control might not be a cause of serious concern if only one or two requests a day were involved, although a case can be made that even one mislaid laboratory request a day is too much, considering the cost of an extra day’s stay in the hospital for one patient; but surprisingly, as many as 10 per cent of the total number of scheduled requests were not filled, as demonstrated by the evidence of the control label processing. The fact that the control label system was needed to uncover this rate of failure is in itself an adequate justification for the necessity of an explicit control procedure. As shown elsewhere, the essence of control is to provide positive evidence that the operation is proceeding correctly; the mere absence of evidence for incorrect operation is not enough. Thus the observed fact, in the old system, that no unfilled requests were returned did not mean that there were none. An example of this principle occurred early in the introduction of the label-processing system. After the experience of the first few days showed that 10 per cent of the requests were uncollected, we noticed that fewer control labels were returned as uncollected apparently showing that the collection rate was rising toward complete collection. Further investigation showed that technicians, when unable to obtain a specimen, were now leaving the control label as well as specimen labels at the nursing station. Control of the controls was finally achieved by counting the control labels before releasing them to the venipuncture team, and by tallying with the count of returned control labels. Having demonstrated the need for and possibility of control in the collection of scheduled specimens, we now propose to use this control information to improve the rate of collection. Measures for this improvement lie outside the scope of this present paper. It is enough to point out that the label-processing system works well when only 90 per cent of the specimens are collected, and that it will work even better as we approach the 100 per cent level. Even if we attain that desired level, we would not expect to abandon the control procedures. They require only a small amount of extra effort on the operation as a whole-an effort which will certainly decrease as we approach 100 per cent-and they provide necessary and adequate safeguards against unforeseen or unauthorized changes in the operation which might allow the rate of collection to fall back to unsatisfactory levels.
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SUMMARY The label-processing system of the Pepper Laboratory covers two-fifths of the daily workload comprising the scheduled early morning blood specimens. This system, providing computer printed labels for the specimens to be drawn by laboratory personnel, saves 70 man-hours a day in technician time with virtually no increase in computer cost. It provides control data on the collection operation which is used to improve the service.