The value of a simple dipstick test (BMtestLN, Boehringer Mannheim-Shionogi) for determination of leukocytes and bacteria in urine was examined. This test consisted of detection of esterase, an enzyme present in leukocytes and the nitrate reduced by bacteria. A total of 666 clinical urine specimens were tested with both tests. The evaluation of leukocytes in urine was compared with microscopic examination, and the identification and measurement of strains was performed using a semiquantitative plate culture method as a reference. The leukocyte esterase test had a sensitivity of 85.3%, a specificity of 67.3%, positive predictive value of 54.7% and negative predictive value of 90.8%. The range of the sensitivity value of nitrate test was 25.7% for the detection of bacteriuria (bacteria greater than or equal to 10(4) CFU/ml). This test had a specificity of 99.6%, positive predictive value of 94.8% and negative value of 82.9%. We concluded that this dipstick test is not useful for determination of the slight change of pyuria, but sensitive for the determination of acute and untreated urinary tract infections.