Two rapid urine screens for detection of bacteriuria: an evaluation

Five hundred twenty-five random clean catch urine specimens, collected from 339 adult females, 137 adult males, and 49 pediatric patients, were screened for the presence of bacteriuria with the Uriscreen catalase test and with the Chemstrip 2 LN dipstick. Quantitative cultures were performed on all specimens. The sensitivity, specificity, positive predictive value, and negative predictive value for the catalase test, with 10(5) CFU/ml as the threshold for significant bacteriuria, were 91.3%, 72.3%, 33.7%, and 98.0%, respectively. Values for the dipstick were 83.9%, 77.9%, 43.7%, and 96.0%. When 10(4) CFU/ml was used as the threshold, the catalase test had a sensitivity of 89.2%, specificity of 70.4%, positive predictive value of 37.3%, and a negative predictive value of 97.0%. Values for the dipstick at that level were 82.3%, 77.5%, 48.6%, and 94.8%. While the catalase test was more sensitive than the dipstick, it was our opinion that high rates of false-negatives associated with these methods negated the convenience of these fast and simple urine screens.