Screening Test for Detection of Urinary Tract Infections: Evaluation of the Urinary Leukocyte Esterase Dipstick Test

AIM/BACKGORUND: To compare the performance of leukocyte esterase dipstick test with microscopic examination in cases with clinically suspected urinary tract infections. METHOD: Freshly urine specimens from 504 patients were analyzed for the presence of white blood cells (WBCs) by leukocyte esterase dipstick test and microscopically WBCs/high power field). A reaction of 1+ or more was taken as a definite indication of significant numbers of leukocytes.Urine dipstick tests were compared with pyuria for each sample. Results were statistically compared. RESULTS: The sensitivity of dipstick leukocyte esterase was found to be 68.5%, whereas the specificity was 73.5%. Microscopic WBCs showed 34% sensitivity with 86.5% specificity. False negative results for leukocyte esterase could occur due to the heavy protienuria, and/or insufficient release of esterase from WBCs. In addition, false negative WBCs count might obtain in case of lyses. CONCLUSION: Leukocyte esterase dipstick urine analysis was considered adequate screening tools in UTI cases. However, caution must be taken in interpreting factors that could affect the results of urine dipstick. Also, leukocyte esterase dipstick urine test was considered as a useful screening test that could be used in population based studies. [TAF Prev Med Bull. 2008; 7(3): 187-190]