Clinical and laboratory evaluation of a rapid screening test for the detection of urinary tract infections in children

ABSTRACT

Recently, dipsticks using nitrite and leukocyte esterase [LE] have become available as markers of urinary tract infection [UTI]. Dipsticks have been extensively tested in adults, but little is known on their use as a routine screening test for the diagnosis of UTI in children to begin presumptive treatment while waiting for the results of the urine culture. To evaluate the reliability of rapid dipstick test as a screening test for the diagnosis of UTI and to determine whether it correlates with the clinical criteria suggestive of UTI in children. A number of 342 schoolchildren were randomly selected from public and private, mixed primary schools located in El Doki and El Mohandesin in Giza governorate. A urine sample was collected from each child, by midstream clean-catch technique in sterile containers. Results of urine dipstick tests for LE and/or nitrite, and microscopic examination of urine [white blood cells] were compared to urine culture results. Dipstick with both nitrite and LE positive had a specificity of 100%, a sensitivity of 93%, 99%, and 98% of positive and negative predictive values respectively. Dipstick of either nitrite or LE positive had a higher sensitivity 99% but a lower specificity 77%. Microscopic examination of urine showed the lowest sensitivity 89%. Results of dipstick [nitrite and LE] and colony count were the highest between all the tests in correlating with clinical criteria suggestive of UTI [Z value 12.23 and 12.25 respectively; p<0.001]. LE and nitrite dipstick urinalysis offers the best combination of test performance characteristics