Serum chemistries for dentists

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Serum chemistry is becoming more complex as newer and more sophisticated diagnostic machinery is used by an increasing number of health care centers. Many automated clinical analyzers can test fo r more than 20 substances from a small sample of serum. The dentist, as part of the health care team, must keep informed of current developments.

Serum chemistries for dentists T h o m a s P. Sh op p er, DDS C harles H . B oozer, DD S, MA

he field o f serum chemistry is con­ stantly becoming m ore complex. New tests, machines, and methods provide m ore precise analysis o f m ore serum constituents in less time. Few arti­ cles1-5 in the literature ha«e dealt with diagnostic laboratory procedures in pa­ tie n t care an d c u rre n t o ral m edicine textbooks6"11 devote a limited num ber o f pages to diagnostic interpretation o f labo­ ratory test results. Reviewed here are the newer tests available in autom ated serum chemistry as well as those that have been available for some time. T he dentist, as a m em ber o f the health care team, should be fa m ilia r w ith this b ra n c h o f clinical pathology. For example, recent graduates begin­ ning a general practice residency or a spe­ cialty program that is based in a hospital may have many medically compromised patients. In such cases, dentist and physi­ cian m ust work together in treatm ent. F u n d a m e n ta l k n o w le d g e o f s e ru m chemistry on the part o f the dental resi­ dent will facilitate communication and in­ teraction. Similarly, today the dentist in private practice is likely to treat ambula­ tory patients with serious medical condi­ tions. F or these instances, a w orking knowledge o f serum analysis may help the dentist provide better care.

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Serum analysis, coupled with studies on whole blood, can be used in two ways in regard to the health o f the dental patient. Several studies1"5 indicate these tests are valuable screening devices to uncover oc­ cult disease. In a screening o f 172 dental patients, Falace1 noted that 22 (16.8%) pa­ tients had at least one abnorm al test value and six (3.5%) patients had two or more, with the most common being elevated glu­ cose 1 h our postprandial. Sabes2 reported that laboratory screening o f 2,245 dental clinic patients showed 14% had abnorm al­ ity o f e ith e r hem oglobin, hem atocrit, blood serology, white blood cell count, or u rin a ly sis. M eyer5 in a p re o p e ra tiv e screening o f 1,349 healthy patients ob­ served that 11.7% o f the patients had ab­ normalities o f the blood o r urine. Medical surveys disclose similar find­ ings. R ardin,12 in surveying a large family practice, accomplished 2,919 laboratory profiles on 1,204 patients. T he conclusion was that 14.2% o f the patients had signs o f unsuspected disease. Laboratory testing by Schoen13 o f 2,000 physicians at an A m erican Medical Association m eeting d u rin g a 5-year period showed 2% of the g ro u p had signs o f undiagnosed disease, mostly relating to blood glucose or blood u rea nitrogen. Laboratory values also can be used to

confirm the definitive diagnosis o f an al­ ready suspected disease or to m onitor its course. Multiple serum analysis for hos­ pitalized patients is routine. For example, a dentist suspecting Paget’s disease o f bone would consider ordering serum analysis for alkaline phosphatase, calcium, and phosphorus levels. Multiple autom ated clinical analyzers are available. Some o f the better known are those m anufactured by Technicon, A m e ric an M o n ito r, H ycel, E astm an Kodak, and DuPont. Perhaps the most widely used, and thus the most familiar to dentists, are the SMA (sequential multiple analyzer) systems. T h e older SMA-6 sys­ tem m e a su re d th e level o f c h lo rid e , sodium, blood urea nitrogen, glucose, and carbon dioxide. Later developm ents were the SMA-12 and SMA-12-60 systems. Test results o f these as well as the SMA-6 are printed as a bar graph which at a glance shows the norm al range for m easured substances, the p atien t’s values, and a com parison o f the two. T he SMA-12 sys­ tem can analyze 12 substances from a serum sample simultaneously. T he most commonly m easured serum chemistries6 are calcium (Ca), inorganic phosphorus (In P), glucose (Gluh), blood urea nitrogen (BUN), uric acid (UA), cholesterol (Choi), total protein (TP), album in (Alb), total JADA, Vol. 114, February 1987 ■ 197

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bilirubin (Bili), alkaline phosphatase, (Aik Phos), lactate dehydrogenese (LDH), and serum glutamic oxaloacetic transam inase (SGOT). Table 1 reviews these 12 sub­ stances, giving the norm al ranges and clin­ ical significance o f a high o r low value. This table is derived largely from Wallach’s text,13 but has been abridged with the dentist in mind. Hence, less common serum tests are not included. T h e newer SMAC and SMA IIC systems

ingested iron toxicity, and pathological in­ creased tra n sfe rrin levels. M ore com ­ monly, when the level of serum iron is low, conditions such as chronic blood loss, malabsorption syndromes, certain malig­ nant cancers, and chronic kidney disease may be suspected. O ften die clinical sig­ nificance o f a specific serum iron level can be ascertained when it is considered with the hemoglobin and hem atocrit values. Triglycerides are esters o f fatty acids

undamental knowledge of serum chemistry on the part of the dentist will facilitate communication and interaction.

can analyze 20 and 24 samples, respec­ tively. Allowances for gender and age dif­ ferences as well as derived values can be program m ed into the com puter o f the SMA IIC. T h e results are usually provided on a com puter p rintout sheet. T h e test perform ed, expected norm al range, and the test’s units are shown. Values outside o f the norm al range are flagged as well as given a num erical value. At Louisiana State University School of Dentistry, all prospective patients have three tubes o f blood drawn by venipunc­ ture at the screening appointm ent. In ad­ dition to other tests, a biochemical profile is developed for each patient. This entails m easurem ent o f 18 serum constituents by an SMA IIC autoanalyzer. T h e normal ranges given are normal values for the geographic area, specif­ ically, the dental school patient popula­ tion. Additionally, newer tests are done, such as: iron, triglycerides, creatine phosp h o k in a s e (C P K ), c r e a t i n e , s e ru m glutamic pyruvic transam inase (SGPT), and serum gamma glutamyl transferase (SGGT). Following is an explanation of these tests, which has been compiled from several sources.14'18 Although most o f the iron in the body is found as working iron in the hemoglobin o f red blood cells, smaller am ounts are seen as storage iron (primarily in the m ar­ row) and as transported iron in the serum. This iron in transit is bound to a plasma protein called transferrin and usually has an expected range o f 50 to 175 mcg/dL. Disease may be suspected when the iron level is either high o r low. Abnormally h ig h iro n v alues a re seen in h em ochromocytosis, hemolytic anemias, acute 198 ■ JADA, Vol. 114, February 1987

and glycerol that are in a dynamic state with body fat, glucose, and amino acids. When transported through the body, they are bound to serum proteins and lipids, such as cholesterol and phospholipids, a n d f o r m c o m p le x li p o p r o t e i n s . Chylomicrons are large aggregates of tri­ glycerides and lipoproteins. In normal pa­ tients, these circulate in the blood in mea­ surable quantities for a few hours after eating. Norm al values in a fasting state are dependent on age and range from 30 to 150 mg/dL. Levels exceeding 400 mg/dL should lead to suspicion o f a potential dis­ ease state. An elevated triglyceride and cholesterol level may be associated with prem ature congestive heart disease and atherosclerosis. High levels of triglyceride also can occur in nephrosis, uncontrolled diabetes mellitus, hypothyroidism , and familial hyperlipoproteinem ia. Decreased

concentrations in cardiac, skeletal, and sm ooth m uscles as well as the brain. Hence, dam age to any o f these tissues will _ result in elevated serum levels of CPK. It is elevated in cerebral vascular accident, m u s c u la r d y s tr o p h y , p o ly m y o sitis, strenuous voluntary muscle exertion, and after a myocardial infarction. Its value is o ften co m p a re d an d co n tra ste d with SGOT and LDH levels after an infarction. CPK is the first enzyme to increase and the first to dissipate after a heart attack. Re­ cently, CPK has been divided into several isoenzymes. This allows the exact tissue of origin (cardiac versus skeletal muscle) to be determ ined. Creatinine is a catabolic end product of creatine that is synthesized in the liver from am ino acids and then transported to muscle. Creatinine, which is not used by the body, is excreted in the urine by the kidney at a nearly constant rate. Its normal serum range is .4 to 1.5 mg/dL and it is this consistency that makes it an excellent as­ sessor o f kidney function. A single, ele­ vated creatinine value would lead the clinician to think o f im paired kidney func­ tion and order m ore specific tests, such as glom erular filtration rate or creatinine clearance. SGPT, an enzyme catalyzing the form a­ tion o f glutamic acid, is found in highest concentrations in the liver. Its normal serum range is 0 to 40 U/L. An elevated serum concentration denotes damage to liver cells as a result o f diseases such as hepatitis, obstructive jaundice, and cir­ rhosis. It is often coupled with the SGOT level and given as a ratio. SGOT is elevated a fte r a m yocardial infarction whereas SGPT is not. SGGT is an enzym e th at relates the tra n sp o rt o f am ino acid th ro u g h cell

dentists, as part of the health care team, should have a working knowledge of serum chemistry tests and their interpretation.

levels o f circulating triglycerides have been noted in m alnutrition and malab­ sorption. CPK is a muscle enzyme catalyzing the tr a n s f e r o f p h o s p h a te g ro u p s fro m creatine phosphate to adenosine diphos­ phate. T he normal range is from 50 to 325 U/L. This enzyme usually is found in high

membranes. Its norm al range is 0 to 65 U/L. This enzyme is widespread in the body with highest concentration in the liver, pancreas, kidney, and repairing h e a rt m uscle. It re a c h e s its h ig h e st pathological elevation in obstructive liver disease such as lower bile duct blockage. It is also significantly elevated in hepatitis,

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Table 1 ■ Most commonly tested serum chemistries. T e s t an d n o rm al ra n g e

U sually elevated in

Usually d e crea sed in

C alcium (C a++) 8.5-10.5 m g /d L

H y p e rp a ra th y ro id ism O steolytic bony m étastasés A cute osteoporosis Excess vitam in D in tak e H y p o p h o sp h a ta sia S o m e e n d o crin o p a th ies H y p e rp ro te in e m ia (sacroid, m yelom a)

H y p o p a ra th y ro id ism M alabsorption o r d e crea sed in ta k e o f vitam in D o r calcium C h ro n ic re n a l disease a n d n e p h ro tic sy n d ro m e H y p o p ro te in e m ia

In o rg a n ic p h o sp h o ru s (In P) 2.5-4.5 m g/dL

C h ild h o o d Active b o n e disease (m yleom a, m y elogenous leukem ia, P ag et’s disease) E xcess vitam in D in ta k e H y p o p a ra th y ro id ism Som e en d o crin o p a th ies

A lcoholism (late) O steom alacia Rickets H y p e rp a ra th y ro id ism D iuretics a n d antacids H y p o p h o sp h a te m ia

G lucose (G luh) 70-110 m g /d L

D iabetes m ellitus P an creatitis S o m e c en tra l n erv o u s system lesions

Excess insulin Excess oral hypoglycem ic d ru g s S evere liver disease Som e en d o crin o p a th ies M aln u tritio n

B lood u re a n itro g e n (B U N ) 5-20 m g/d L

Im p a ire d kidney fu n c tio n (ren al failure, azo tem ia, congestive h e a r t failure) In c re a se d p ro te in catabolism

Severe liver d a m a g e (d ru g s, hepatitis) D iet— low p ro te in , h ig h c a rb o h y d ra te

U ric acid (UA) 2.2-9 m g /d L

R enal failure G out N u c leo p ro te in d e stru c tio n (som e m alignancies, c h em o th erap y ) Diet— h ig h p ro te in in tak e

U ricosuric d ru g s (high-dose salicylates, c ortisone, coum arins) A crom egaly

C holesterol (Choi) 120-275 m g /d L

B iliary tra c t o b stru c tio n P a n creatic disease P reg n an cy H y p o th y ro id ism

S evere liver disease M alnutrition S om e c h ro n ic anem ias H y p e rth y ro id ism

T o ta l p ro te in (TP) 6.0-8.5 g/dL

M ultiple m yelom a (and o th e r gam m opathies) Som e collagen diseases (lu p u s, rh e u m a to id arthritis) Sarcoidosis

H o d g k in ’s disease a n d m onocyctic leukem ia G astrointestinal disease— p e p tic ulcer, ulcerative colitis, cholecystitis C h ro n ic g lo m e ru lo n e p h ritis

A lbum in (Alb) 2.6-5.2 g/dL

N o t g en erally seen

In a d e q u a te p ro te in intake Severe liver disease Som e collagen diseases S om e acute a n d c hronic in flam m a tio n M ultiple m yelom a H y p e rth y ro id ism

T o ta l b ilirubin (Bili) 1-1.2 m g /d L

H ep atitis B iliary tra c t o b stru ctio n H em olytic disease P ro lo n g ed fasting

N o t generally seen

A lkaline p h o sp h ata se (Aik Phos) 30-115 U /L

C h ild h o o d Diseases an d c o n d itio n s cau sin g in creased deposition o f b o n e (P aget’s disease, h e alin g fractures, osteoblastic tu m o rs, rickets, late pregnancy) O b stru ctiv e liver disease H y p e rp h o sp h a ta sia H y p e rp a ra th y ro id ism

M alnutrition Excess vitam in D intake P ernicious an em ia H y p othyroidism H y p o p h o sp h a ta sia

Lactic d e h y d ro g e n ase (LD H ) 100-225 U /L

M yocardiac in farctio n O th e r m uscle in fa rc tio n H em olytic an em ias H ep atitis L eu k em ia an d ly m p h o m a Som e re n a l diseases

Irra d ia tio n

S e ru m g lutam ic oxaloacetic tra n sam in ase (SG O T) 0-40 U/L

M yocardial in farctio n M usculoskeletal disease Liver disease (hepatitis, cirrhosis, h epatic m étastasés, o b stru ctio n ) Pancreatitis C e reb ral in farctio n

C h ro n ic hem odialysis B eriberi

Shopper-B oozer : SERUM C H E M IS T R IE S FO R D E N T IST S ■ 199

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cirrhosis, metastatic liver disease, certain pancreatic diseases, and healing h eart muscle. As a diagnostic aid, its value is com pared and contrasted with oth er liver enzym es (SG O T , SGPT) an d alkaline phosphatase levels. Of all these liver dam ­ age indicators, SGGT is the most sensitive. Conclusions Serum chemical analysis has become more complex as new tests, machines, and sys­ tems have provided m ore precise analysis of'a greater num ber of constituents in less time. Dentists, as m embers o f the health care team, should have a working knowl­ edge o f serum chemistry tests and their diagnostic in te rp re ta tio n . D ata on the most common constituents in biochemical profiles are given in tabular form. ---------------------- J'A O A ---------------------In fo rm a tio n a b o u t th e m a n u fa c tu re rs o f th e p ro d ­ ucts m e n tio n e d in this article m ay be available fro m th e a u th o rs. N e ith e r th e a u th o rs n o r th e A m e ric a n D ental

A ssociation has any com m ercial interests in th e p ro d ­ ucts m e n tio n e d . D r. S h o p p e r is associate p ro fesso r, a n d D r. B oozer is p ro fesso r an d ch air, d e p a rtm e n ts o f o ral diagnosis, m e d ic in e , a n d r a d io lo g y , S c h o o l o f D e n tis tr y , L ouisiana State U niversity, 1100 F lorida Ave, New O rlean s, 70119-2799. A d d re ss re q u e sts fo r re p rin ts to Dr. S h o p p er. 1. Falace, D. A n e v alu atio n o f th e clinical laboratory as an a d ju n c t to d e n ta l practice. JA D A 96(2):261-265, 1978. 2. Sabes, W .R., a n d o th e rs. V alue o f m edical d ia g ­ n o stic s c r e e n in g te sts f o r d e n ta l p a tie n ts . JA D A 80(1): 133-136, 1970. 3. B arre tt, R. D iagnostic la b o ra to ry tests — who need s it? J A m Soc Prev D en t 3(6):26-28, 1973. 4. S ab es, W .R ., a n d B lozis, G .G . T h e c linical lab o rato ry — w hat it m eans to you a n d y o u r p atients. J A m Soc Prev D ent 3(6):33-35, 1973. 5. M eyer, R.A. P reo p e ra tiv e lab o rato ry screening b efo re a d m in istra tio n o f g e n e ra l an esth esia in th e o f­ fice. J O ra l S u rg 28:332-334, 1970. 6. H alstead , C .L., a n d o th e rs. Physical evaluation o f th e d e n ta l p atient. St. Louis, C. V. Mosby C o, 1982, p p 362-371. 7. Lynch, M .A.; B rig h tm a n , V .J.; a n d G reen b erg , M.S. B u rk e t’s o ral m edicine, e d 8. P hiladelphia, J . B. L ip p in co tt Co, 1984, p p 83-100.

8. K e rr, D .A .; A sh, M .M .; a n d M illard, H .D . O ral diagnosis, ed 5. St. Louis, C. V. Mosby, 1978, p p 329333. 9. M itchell, D .F.; S tan d ish , S.M.; a n d Fast, T .B . ~ O ral diagnosis/oral m edicine, ed 3. Philadelphia, Lea & F ebiger, 1978, p p 220-230. 10. Zegarelli, E.V .; K utscher, A .H .; a n d H ym an, G.A. D iagnosis of diseases o f th e m o u th a n d jaw s, e d 2. P hiladelphia, Lea & F ebiger, 1978, pp 20-24. 11. T u llm an , M.J., a n d R edding, S.W. Systemic dis­ ease in d e n ta l tre a tm e n t. New Y ork, A ppleton-C entury -C ro fts, 1982, p p 471-475. 12. R ard in , T .E . L a b o ra to ry profile screen in g in fam ily practice. JA M A 214(7): 1262-1268, 1970. 13. S choen, I. C linical chem istry— a retrospective look a t ro u tin e screen in g . C alif M ed 108(6):430-436, 1968. 14. W allach, J . In te rp re ta tio n o f diagnostic tests, ed 3. B oston, Little, B row n a n d Co, 1979. ^ 15. L arson, F.C. C linical significance o f tests avail­ able o n th e D u P o n t a u to m a tic clinical analyzer, Wil­ m ing to n : D u P o n t Co, N D. 16. P resto n , J.A ., a n d T ro x e l, D.B. Biochem ical pro filin g in diagnostic m ed icin e, vol 1, 2. T a rry to w n , NY, T e c h n ic o n In s tru m e n ts C o rp , 1974. 17. Sabes, W .R. T h e d e n tist a n d clinical laboratory p ro c e d u re s. St. Louis, C. V. Mosby Co, 1979. 18. K ru p p , M.S., a n d C h atto n , M.J. C u rre n t m edi­ cal diagnosis a n d tre a tm e n t. Los Altos, CA, Lange M edical Publications, 1984.

The use of fiberoptic handpieces in dentistry may have advanced faster than has the knowledge on how to use them. Differences in brightness are extreme in the dentist’s work environment and may result in the dentist’s experiencing fatigue. This article discusses lighting of the operating field in general, presents basic characteristics of available hand­ piece fiberoptic systems, and provides the dental practitioner with guidelines for adjust­ ment and safe use of intraoral fiberoptic lighting.

Dental fiberoptic handpieces: recommendations for proper use Joh n R. G ildersleeve, DDS Jack L. Hardage, DDS John M. Y oung, DDS, MSc

ince the 1970s, dentists increasingly have depended on dental fiberoptic handpieces to improve access to and lighting of the m outh.1Fiberoptics are one of the most popular additions to dental technology; however, the use of fiberoptics may have advanced faster than has the knowledge of how to use them. A review of the literature discloses a paucity of infor­ mation for the practicing dentist concern­

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200 ■ JADA, Vol. 114, February 1987

ing installation, adjustment, expectations, use, maintenance, and safety of dental fiberoptic handpieces. T his article discusses lighting of the operating field in general, presents basic characteristics of available fiberoptic hand­ piece systems, and provides the dental prac­ titioner with guidelines for adjustment and safe use of intraoral fiberoptic lighting. T o see better, some dentists have mistak­

enly used quantity rather than quality of light when illum inating the mouth. As long as the work task was well lighted, little attention was paid to comparative lighting of the environment outside the patient’s mouth. Differences in brightness are extreme in the dentist’s work environ­ ment and result in fatigue. It has been reported2 that lighting engineers estimate that 90% of the fatigue experienced by den-