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Dipstick testing of urine
Clinical Radiology (1997) 52, 566-568
Correspondence Letters are published at the discretion of the Editor. Opinions expressed by correspondents are not necessarily those of the Editor. Unduly long letters may be returned to the authors for shortening. Letters in response to a paper may be sent to the author of the paper so that the reply can be published in the same issue. Letters should be typed double spaced and should be signed by all authors personally. References should be given #z the style specified in the Instructions to Authors at the front of the Journal.
DIPSTICK TESTING OF URINE Sra - I have read with interest the article of Rockall et aL [1]. The authors correctly state that dipstick testing of urine for haematuria may be positive in some normal patients. However it is bold to say that it is essential that the result should be confirmed microscopically in all cases before an IVU is requested. It is true that if the very sample that was dipstick positive is examined and shown not to have any red cells then this can be regarded as a false positive. However it is increasingly common to be refen'ed patients in whom a positive dipstick result alone is the ieasnn for referral. To only proceed with investigations after a subsequent sample has been microscoped to confirm haematuria may be dangerous. Messing et al. [2] detected eight patients with urological malignancy from 44 men over the age of 50 with asymptomatic dipstick positive haematuria. In all these eight patients, dipstick results were only intelanittently positive when tested on a daily basis from first detection until formal evaluation occurred. Six of these eight patients had negative microscopic examinations at the start of evaluation. Lynch et al. [3] found that 35 out of 65 (56%) patients referred for asymptomatic microscopic haematuria had no detectable haematuria on microscopic examination of urine when first seen in clinic. Two of these 35 were found to have bladder cancer. The prevalence of urological malignancies under the age of 40 is low. Therefore the positive predictive value of a positive dipstick result for detecting malignancies is also low. Some studies have even concluded that it is not worthwhile investigating asymptomatc microscopic haematuria in patients under 40 [4]. Above this age the percentage of malignancies associated with a positive dipstick result increases. The intermittent nature of malignant haematuria means that to ignore a single positive result because of a subsequent microscopy may be dangerous especially in the older age group. A. JONES
Department of Urology Northampton General Hospital Northampton, UK
References 1 Rockall AG, Wetton CWN, Thomas KE, Kellett MJ. A three centre audit of IVU referrals in patients with asymptomatic microscopic haematuria. Clinical Radiology 1996;51:282-284. 2 Messing EM, Young TB, Hunt VB et al. Urinary tract cancers found by home screening with haematuria dipsticks in healthy men over 50 years of age. Cancer 1989;64:2361-2367. 3 Lynch TH, Waymont B, Dunn JA, Hughes MA, Wallace DMA. Repeat testing for haematuria and underlying urological pathology. British Journal of Urology 1994;74:730-732. 4 Froom P, Ribak J0 Beubassat J. Significance of microhaematuria in young adults. British Medical Journal 1984;288:20-22.
SiR - The audit which we performed [l] used as a standard of practice an algorithm published by a Professor of Urology, in the British Medical Journal [2]. The incidence of urological malignancies does indeed increase with age. One per cent of bladder cancers present in the under 40s, 4% in the under 50s and the peak incidence in men is in the 65-69 age group [3]. In our audit of asymptomatic patients, 16.7% were under the age of 40 and less than half of these had microscopic confirmation of haematuria. Fourteen per cent of patients had a proven urinary tract infection but the IVU was requested prior to the MSU result or reconfirmation of haematuria following treatment of the UTI. This does suggest that a positive dipstick result is leading to some unnecessary referrals for 1VU. In Messing's study [4], 44 of the 235 men screened had one or more episode of dipstick positive haematuria. Thus 18.7% of this population required full urological work-up to exclude a cancer. The feasibility of investigating nearly one-fifth of the male population over the age of 50 based on this screening criteria must be scrutinized. And indeed, in those © 1997 The Royal College of Radiologists.
patients in whom no abnormality is detected, the repeat screening interval and interval for re-investigation in those with furtber episodes of haematuria is not clear. In Lynch's study [5], the authors state that the low MSU positivity rate may have been due to all samples being obtained when patients had a full bladder, resulting in dilution and possibly red cell lysis. Clearly, there is much debate concerning screening for haematuria to detect urological malignancies. The intermittent nature of haematuria coupled with a fairly high false positive rate for dipsticks (9% to 15%) [6-8] create screening difficulties. A high risk group based on age criteria may be selected for screening, but to fully investigate an estimated 20% of the screened population would certainly be an enormous strain on current services. A more specific screening tool is avidly awaited. A. ROCKALL M. KELLETT K. THOMAS C. WETTON
Department of Radiology The Middlesex Hospital Mortimer Street London UK
References 1 Rockall AG, Wetton CWN, Thomas KE, Kellett MJ. A three centre audit of IVU referrals in patients with asymptomatic microscopic haematuria. Clinical Radiology 1996;51:282-284. 2 Schroder FH. Microscopic haematuria: requires investigation. British Medical Journal 1994;309:70-72. 3 0 P C S , Registrations of cancer diagnoses in 1989, England and Wales. Cancer Statistics: Registrations 1994;MB1 (No. 22), London: HMSO. 4 Messing EM, Young TB, Hunt VB, Wehbie JM, Rust P. Urinary tract cancers found by homescreening with hematuria dipsticks in healthy men over 50 years of age. Cancer 1989;64:2361-2367. 5 Lynch TH, Waymont B, Dunn JA, Hughes MA, Wallace DMA. Repeat testing for haematuria and underlying urological pathology. British Journal of Urology 1994;74:730-732. 6 Arm JP, Peile EB, Rainford DJ, Strike PW, Tettmar RE. Significance of dipstick haematuria. 1. Correlation with microscopy of the urine. British Journal of Urology 1986;58:211-217. 7 Bonnardeanx A, Somerville P, Kaye M. A study of the reliability of dipstick urinalysis. Clinical Nephrology 1994;41(3):167-172. 8 Gleeseon MJ, Connolly J, Grainger R, McDermott TED, Butler MR. Comparison of reagent strips (dipstick) and microscopic haematuria in urological out-patients. British Journal of Urology 1993;72:594--596.
THE IMPACT OF CORE-BIOPSY ON PRE-OPERATIVE DIAGNOSIS RATE OF SCREEN-DETECTED BREAST CANCERS S ~ - We wish to comment on the recent paper above of Litherland et al. [1]. We believe it gives the wrong impression of the utility of fine needle aspiration (FNA) versus core biopsy (CB) and could lead to the loss of tbe very real benefits of FNA, namely that a diagnosis can be made on the day of aspiration and that in many cases definitive treatment can be planned. Admittedly, FNA cannot distinguish invasive from non-invasive disease, information required prior to embarking on axillary clearance. However, consideration of mammographic and clinical features in a multi-disciplinary setting can predict invasion with a high degree of accuracy. In those cases which are indeterminate CB may well miss a tiny invasive focus. This paper is a retrospective study, limited to histologically confirmed cancers. The authors give FNA very little chance and seem to have decided that in their hands FNA was of limited value, though there is insufficient information in the methods section to judge this point. Certainly, FNA is a difficult technique to learn, both for aspirators and cytopathologists, in our unit the learning curve lasted nearly 2 years even starting from what we thought was a reasonable level of skill. We are now achieving 61% malignant (C5) aspirates from DCIS, almost all of which are microcalcifications. Image-guided FNA particularly requires careful, and if necessary repeat, sampling with immediate checking of aspirate cellularity. Immediate reporting is integral to this approach.
Correspondence Letters are published at the discretion of the Editor. Opinions expressed by correspondents are not necessarily those of the Editor. Unduly long letters may be returned to the authors for shortening. Letters in response to a paper may be sent to the author of the paper so that the reply can be published in the same issue. Letters should be typed double spaced and should be signed by all authors personally. References should be given #z the style specified in the Instructions to Authors at the front of the Journal.
DIPSTICK TESTING OF URINE Sra - I have read with interest the article of Rockall et aL [1]. The authors correctly state that dipstick testing of urine for haematuria may be positive in some normal patients. However it is bold to say that it is essential that the result should be confirmed microscopically in all cases before an IVU is requested. It is true that if the very sample that was dipstick positive is examined and shown not to have any red cells then this can be regarded as a false positive. However it is increasingly common to be refen'ed patients in whom a positive dipstick result alone is the ieasnn for referral. To only proceed with investigations after a subsequent sample has been microscoped to confirm haematuria may be dangerous. Messing et al. [2] detected eight patients with urological malignancy from 44 men over the age of 50 with asymptomatic dipstick positive haematuria. In all these eight patients, dipstick results were only intelanittently positive when tested on a daily basis from first detection until formal evaluation occurred. Six of these eight patients had negative microscopic examinations at the start of evaluation. Lynch et al. [3] found that 35 out of 65 (56%) patients referred for asymptomatic microscopic haematuria had no detectable haematuria on microscopic examination of urine when first seen in clinic. Two of these 35 were found to have bladder cancer. The prevalence of urological malignancies under the age of 40 is low. Therefore the positive predictive value of a positive dipstick result for detecting malignancies is also low. Some studies have even concluded that it is not worthwhile investigating asymptomatc microscopic haematuria in patients under 40 [4]. Above this age the percentage of malignancies associated with a positive dipstick result increases. The intermittent nature of malignant haematuria means that to ignore a single positive result because of a subsequent microscopy may be dangerous especially in the older age group. A. JONES
Department of Urology Northampton General Hospital Northampton, UK
References 1 Rockall AG, Wetton CWN, Thomas KE, Kellett MJ. A three centre audit of IVU referrals in patients with asymptomatic microscopic haematuria. Clinical Radiology 1996;51:282-284. 2 Messing EM, Young TB, Hunt VB et al. Urinary tract cancers found by home screening with haematuria dipsticks in healthy men over 50 years of age. Cancer 1989;64:2361-2367. 3 Lynch TH, Waymont B, Dunn JA, Hughes MA, Wallace DMA. Repeat testing for haematuria and underlying urological pathology. British Journal of Urology 1994;74:730-732. 4 Froom P, Ribak J0 Beubassat J. Significance of microhaematuria in young adults. British Medical Journal 1984;288:20-22.
SiR - The audit which we performed [l] used as a standard of practice an algorithm published by a Professor of Urology, in the British Medical Journal [2]. The incidence of urological malignancies does indeed increase with age. One per cent of bladder cancers present in the under 40s, 4% in the under 50s and the peak incidence in men is in the 65-69 age group [3]. In our audit of asymptomatic patients, 16.7% were under the age of 40 and less than half of these had microscopic confirmation of haematuria. Fourteen per cent of patients had a proven urinary tract infection but the IVU was requested prior to the MSU result or reconfirmation of haematuria following treatment of the UTI. This does suggest that a positive dipstick result is leading to some unnecessary referrals for 1VU. In Messing's study [4], 44 of the 235 men screened had one or more episode of dipstick positive haematuria. Thus 18.7% of this population required full urological work-up to exclude a cancer. The feasibility of investigating nearly one-fifth of the male population over the age of 50 based on this screening criteria must be scrutinized. And indeed, in those © 1997 The Royal College of Radiologists.
patients in whom no abnormality is detected, the repeat screening interval and interval for re-investigation in those with furtber episodes of haematuria is not clear. In Lynch's study [5], the authors state that the low MSU positivity rate may have been due to all samples being obtained when patients had a full bladder, resulting in dilution and possibly red cell lysis. Clearly, there is much debate concerning screening for haematuria to detect urological malignancies. The intermittent nature of haematuria coupled with a fairly high false positive rate for dipsticks (9% to 15%) [6-8] create screening difficulties. A high risk group based on age criteria may be selected for screening, but to fully investigate an estimated 20% of the screened population would certainly be an enormous strain on current services. A more specific screening tool is avidly awaited. A. ROCKALL M. KELLETT K. THOMAS C. WETTON
Department of Radiology The Middlesex Hospital Mortimer Street London UK
References 1 Rockall AG, Wetton CWN, Thomas KE, Kellett MJ. A three centre audit of IVU referrals in patients with asymptomatic microscopic haematuria. Clinical Radiology 1996;51:282-284. 2 Schroder FH. Microscopic haematuria: requires investigation. British Medical Journal 1994;309:70-72. 3 0 P C S , Registrations of cancer diagnoses in 1989, England and Wales. Cancer Statistics: Registrations 1994;MB1 (No. 22), London: HMSO. 4 Messing EM, Young TB, Hunt VB, Wehbie JM, Rust P. Urinary tract cancers found by homescreening with hematuria dipsticks in healthy men over 50 years of age. Cancer 1989;64:2361-2367. 5 Lynch TH, Waymont B, Dunn JA, Hughes MA, Wallace DMA. Repeat testing for haematuria and underlying urological pathology. British Journal of Urology 1994;74:730-732. 6 Arm JP, Peile EB, Rainford DJ, Strike PW, Tettmar RE. Significance of dipstick haematuria. 1. Correlation with microscopy of the urine. British Journal of Urology 1986;58:211-217. 7 Bonnardeanx A, Somerville P, Kaye M. A study of the reliability of dipstick urinalysis. Clinical Nephrology 1994;41(3):167-172. 8 Gleeseon MJ, Connolly J, Grainger R, McDermott TED, Butler MR. Comparison of reagent strips (dipstick) and microscopic haematuria in urological out-patients. British Journal of Urology 1993;72:594--596.
THE IMPACT OF CORE-BIOPSY ON PRE-OPERATIVE DIAGNOSIS RATE OF SCREEN-DETECTED BREAST CANCERS S ~ - We wish to comment on the recent paper above of Litherland et al. [1]. We believe it gives the wrong impression of the utility of fine needle aspiration (FNA) versus core biopsy (CB) and could lead to the loss of tbe very real benefits of FNA, namely that a diagnosis can be made on the day of aspiration and that in many cases definitive treatment can be planned. Admittedly, FNA cannot distinguish invasive from non-invasive disease, information required prior to embarking on axillary clearance. However, consideration of mammographic and clinical features in a multi-disciplinary setting can predict invasion with a high degree of accuracy. In those cases which are indeterminate CB may well miss a tiny invasive focus. This paper is a retrospective study, limited to histologically confirmed cancers. The authors give FNA very little chance and seem to have decided that in their hands FNA was of limited value, though there is insufficient information in the methods section to judge this point. Certainly, FNA is a difficult technique to learn, both for aspirators and cytopathologists, in our unit the learning curve lasted nearly 2 years even starting from what we thought was a reasonable level of skill. We are now achieving 61% malignant (C5) aspirates from DCIS, almost all of which are microcalcifications. Image-guided FNA particularly requires careful, and if necessary repeat, sampling with immediate checking of aspirate cellularity. Immediate reporting is integral to this approach.