Streamlining Urinary Tract Infection Evaluation in a Large Pediatric Hospital System: Feasibility of Reflex Urine Culture After Urinalysis With Microscopy.

Abstract

Reflex urine culture testing can reduce unnecessary cultures, limit inappropriate antibiotic use for asymptomatic bacterial presence, and lower health care costs. In pediatrics, considerations include patient age, specimen collection method, and evidence-based urinalysis criteria to identify clinically significant urinary tract infections. To determine how many positive urine cultures would be missed if a reflex urine culture approach were applied in a large pediatric hospital system. A retrospective review of pediatric urine samples collected for ∼10 months with concurrent urinalysis (chemical and microscopic) and urine culture results was performed. Urinalysis was considered positive if 1 or more of the following were present: leukocyte esterase, nitrite, more than 10 white blood cells per high-power field, or bacteria. Positive urinalysis results were compared with urine culture thresholds of 1000 colony-forming units per milliliter (CFU/mL) or greater; 10 000 CFU/mL or greater; and 50 000 CFU/mL or greater in catheter and nonsterile urine collections. Of 6926 samples, 1520 (21.9%) were catheter collections and 5406 (78.1%) were nonsterile. Applying urine culture thresholds of 10 000 CFU/mL or greater and 50 000 CFU/mL or greater for catheter and nonsterile collections, respectively, a negative urinalysis finding demonstrated a high negative predictive value (≥96.6%). A reflex culture protocol would have eliminated 3652 of 6926 cultures (52.7%) and would have missed 71 of 6926 total samples (1.0%). Organisms other than Escherichia coli were more frequently isolated from cultures that were negative by urinalysis. Implementing reflex urine culture testing based on positive urinalysis results can help reduce unnecessary urine cultures in the pediatric population with a high negative predictive value.