Evaluation of the Chemstrip 9 as a screening test for urinalysis and urine culture in men.

The Chemstrip 9 (Biodynamics, Inc., Indianapolis, IN) was evaluated as a rapid screening method for urinalysis and quantitative urine culture. Of 469 urine specimens, 224 had an abnormal microscopic examination compared to 211 with an abnormal Chemstrip 9 (i.e., leukocyte esterase, nitrite, protein, or blood). The sensitivity and specificity of the dipstick test were 94.2% and 65.7%, respectively, while the predictive values of a positive and negative test were 71.5% and 92.5%, respectively. A total of 459 urine specimens were quantitatively cultured and tested by the Chemstrip 9. Either one or more tests (i.e., leukocyte esterase, nitrite, protein, or blood) were positive in 91.3% of the 115 specimens with greater than or equal to 10(5) CFU/mL. The specificity was 43.6% and the predictive values of a positive and negative test were 35.1% and 93.8%, respectively. When the criterion for a positive test was greater than or equal to 10(4) CFU/mL, the sensitivity and specificity were 86.8% and 45.5%, respectively. In contrast, the gram-stained smear of unspun urine was positive in 107 (93.0%) of specimens containing greater than or equal to 10(5) CFU/mL and in 115 (76.2%) of specimens with greater than or equal to 10(4) CFU/mL. Only 9 (2.9%) of 308 specimens with less than or equal to 10(3) CFU/mL had a positive Gram smear.