Performance characteristics of urinalyses for the diagnosis of pediatric urinary tract infection

Purpose

The purpose of this study is to determine whether point-of-care (POCT) urinalysis (UA) is as accurate as laboratory-performed UA in diagnosing urinary tract infections (UTIs) in the pediatric emergency department (PED).

Basic procedures

This was a retrospective series of children (0-18 years old) seen at a tertiary care PED from July 2008 to December 2012 in whom UA and urine culture were obtained. Urinalyses were considered positive if leukocyte esterase and/or nitrites were positive. Performance characteristics for the 2 types of UAs were calculated using urine culture as the reference standard.

Main findings

A total of 43 452 specimens were sent for laboratory-performed UA and culture, and 6492, for POCT UA and culture (in 2908 specimens, both UAs were performed). Sixty-four percent of specimens were from girls, 51% were catheterized, and 7.5% had UTIs. The sensitivity of POCT UAs and laboratory-performed UAs was 82.5% (confidence interval [CI], 79.4%-85.3%) and 89.1% (CI, 86.4%-88.8%), respectively. The superior performance of laboratory-performed UAs was driven by the sensitivity of microscopy. Laboratory-performed UAs were more sensitive than the POCT in girls (90.6% [CI, 89.4%-91.8%] vs 82.8% [79.4%-85.8%]).

Principal conclusions

Although POCT UAs offer more rapid turnaround times, the sensitivity is greater for laboratory-performed UAs. Given the difficulty in following up PED patients after discharge as well as the potential morbidity from untreated UTIs, the rapidity of the POCT UA must be balanced against the lower sensitivity of this assay. The benefit of more accurate diagnosis may outweigh the potentially longer PED length of stay associated with a laboratory-performed UA.