PROS Pearls:

* As part of the Febrile Infant Study, investigators determined predictors of urethral catheterization in febrile infants and compared bag and catheterized urine test performance characteristics.

* Of the 3066 infants enrolled, at the initial visit a UA was performed on 1639 (53%) infants, and a urine culture was obtained from 1605 (52%) infants. A total of 1763 patients had either a UA or urine culture, whereas 1482 patients had both a UA and urine culture at presentation. Seventy percent of urine samples were obtained by catheterization.

* Infection rates were similar in bag and catheterized specimens (8.5% vs 10.8%), but bag urine cultures were more likely to have: 1) 2 organisms; 2) nonpathogenic bacteria; and 3) an ambiguous result.

* Predictors of catheterization included 1) female sex; 2) practitioner younger than 40 years; 3) Medicaid; 4) Hispanic ethnicity; 5) nighttime evaluation; and 6) severe dehydration.

* The association between young practitioner age and increased catheterization may reflect evolving training practices, the fact that younger practitioners tend to adhere more closely to guidelines than older practitioners, or a propensity by younger practitioners to do or order more procedures.

* The authors conclude that most practitioners obtain urine from febrile infants via catheterization but they do not base decisions to catheterize on the pretest probability of UTI. Although both urine cultures and urinalyses are more accurate in catheterized specimens, the magnitude of difference is small but should be factored into clinical decision making. Further studies that compare urinalyses obtained simultaneously in the same patient by both methods would help to substantiate or refute our findings.