The validity of the uriscreen test for early detection of urinary tract infection in children

Objective. To determine the validity of the Uriscreen, a rapid diagnostic t est based on the detection of urine catalase for the early detection of uri nary tract infection (UTI) in children, compared with standard urinalysis a nd dipstick tests. Study Design. Cross-sectional study. Study Population. Children 1 month to 17 years of age who presented to the emergency department of a pediatric tertiary care center between March and November of 1996 with symptoms suggestive of UTI. Methods. Urine specimens obtained from a random sample of 121 patients were evaluated simultaneously for possible UTI by Uriscreen (catalase test), ur inalysis (microscopic pyuria), dipstick (leukocyte esterase and nitrite), a nd quantitative urine culture. All specimens were collected by one of three sterile techniques (midstream void technique, bladder catheterization, or suprapubic aspiration), as appropriate for age, and tested immediately. Usi ng the quantitative urine culture as the gold standard (reference test), th e sensitivity, specificity, and positive and negative predictive values of all the screening tests were determined and compared. Age, sex, temperature , presenting symptoms, and method of urine collection were recorded for eac h participant. Results. Of the 121 patients, 35 (28.9%) had positive culture results: 30 g irls (85.7%) and 5 boys (14.3%). Compared with urinalysis and dipstick test s, Uriscreen had the highest sensitivity (100% vs 88.6% and 97.1%, respecti vely) and the highest negative predictive value (100% vs 95% and 98.6%, res pectively), but the poorest specificity (68.6% vs 88.4% and 82.5%, respecti vely) and positive predictive value (56.4% vs 75.6% and 69.4%, respectively ). Conclusions. The clinical use of Uriscreen for the presumptive diagnosis of UTI in children is limited and not significantly superior to urinalysis or the dipstick test. However, because of its 100% sensitivity and negative p redictive value and its ease of use, rapidity, and low cost, it is recommen ded highly for ruling out the diagnosis of UTI. In laboratories, a negative Uriscreen result may prevent the need for performing expensive urine cultu res.