We compared the performance of leukocyte esterase and nitrite reductase dipstick tests with microscopic examination and uroculture in cases with clinically suspected urinary tract infection (UTI). We studied urine specimens from 504 Jordanian patients which were obtained by the mid-stream clean catch method and analyzed for bacteria. All samples were subjected to culture. Results of urine dipstick tests and pyuria (white blood cells (WBC)/high power field) were compared with urine culture for each sample. Significant bacteriuria was found in 117 cases (23.2%) with positivity of 59% and 68.5% for the presence of nitrite reductase and leukocyte esterase, respectively. Echerichia coli was the most common organism isolated. The dipstick leukocyte esterase and nitrite testing had a sensitivity of 68.5% and 59% for detecting bacteriuria in UTI cases and specificity of 73.5% and 78%, respectively. The positive predictive value of the tests was 44% and 60%, and the negative predictive value 88.5% and 86.2%, respectively. Microscopic WBC showed 86.5% specificity but low sensitivity. Urine dipstick results and pyuria significantly correlated with the results of urine culture but demonstrated more false-positive results, which ranged from 13.4–26.6%. The probability of growing a urinary pathogen correlated with urinary WBC counts and allowed prediction of the presence or absence of bacteriuria by counting urinary leukocytes. A combination of pyuria and urine dipstick testing appears to be a very useful marker for the diagnosis of UTI. Urine culture can be omitted if both tests are negative.
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