CLINICAL QUESTION

Is a urine dipstick analysis to identify or rule out urinary tract infection (UTI) in febrile infants 2 to 6 months of age as accurate as urinalysis?

BOTTOM LINE

A urine dipstick test is as accurate as urinalysis for identifying UTI in febrile infants 2 to 6 months of age. The presence of nitrite or leukocyte esterase of 1+ or greater can be used for diagnosis; the absence of both rules out UTI in 99% of cases. (Level of Evidence = 1b)

SYNOPSIS

The study included 9,387 febrile infants 2 to 6 months of age who were in five pediatric hospital emergency departments in the United States and had a catheterized urine culture obtained. Urine samples were evaluated for nitrite or leukocyte esterase via a urine dipstick test and for white blood cell count by urinalysis. Using a white blood cell cutoff of 7 cells per high-power field, urine dipstick findings of nitrite or leukocyte esterase of 1+ or more had a 90.2% sensitivity (95% CI, 88.1%–92.1%) and 92.6% specificity (95% CI, 91.9%–93.2%), both of which were higher than urinalysis. Given the 11.1% rate of UTIs in this group, these characteristics translate into a positive predictive value of 62% and a negative predictive value of 98.6%.