Aim: Although, urine culture requests to diagnose urinary tract infection (UTI) are very common, about 70-80% of urine samples received in the laboratory are found to be negative. This means increased laboratory workload and cost. Urinary leukocyte esterase and nitrite are quick, easy and inexpensive tests. The aim of this study was to evaluate the diagnostic performance of nitrite and leukocyte esterase for prediction of urine culture with respect to age and gender.

Materials and Methods: In this retrospective study 24788 samples were included, which both urine culture and urinalysis were requested simultaneously. For the diagnostic performances, leukocyte esterase and nitrite results were compared to urine culture results.

Results: 3544 (14.3%) samples were positive for bacteriuria by urine culture. The sensitivity of leukocyte esterase was 74.6% and nitrite was 43.1%. The specificities were 64.2% and 99%, respectively. If being leukocyte esterase and nitrite both positive or either of them positive is considered to be a positive result, the sensitivity and specificity were 81.3% and 64%, respectively. For the sensitivity and specificity of nitrite, there was no difference between male and female samples. The sensitivity values of leukocyte esterase for both gender were similar, but its specificity was significantly higher in male subjects. No difference was obtained pertaining age.

Conclusion: Positive nitrite results should be considered as an indicator for UTI. However, negative nitrite results do not exclude UTI. Leukocyte esterase results have poor performance for both ruling in and ruling out UTI. Negative leukocyte esterase and nitrite results have the best performance as ruling out UTI.