Dipstick screening for urinary tract infection in febrile infants.
OBJECTIVE
This study compares the performance of urine dipstick alone with urine microscopy and with both tests combined as a screen for urinary tract infection (UTI) in febrile infants aged 1 to 90 days.


METHODS
We queried the Intermountain Healthcare data warehouse to identify febrile infants with urine dipstick, microscopy, and culture performed between 2004 and 2011. UTI was defined as >50 000 colony-forming units per milliliter of a urinary pathogen. We compared the performance of urine dipstick with unstained microscopy or both tests combined ("combined urinalysis") to identify UTI in infants aged 1 to 90 days.


RESULTS
Of 13 030 febrile infants identified, 6394 (49%) had all tests performed and were included in the analysis. Of these, 770 (12%) had UTI. Urine culture results were positive within 24 hours in 83% of UTIs. The negative predictive value (NPV) was >98% for all tests. The combined urinalysis NPV was 99.2% (95% confidence interval: 99.1%-99.3%) and was significantly greater than the dipstick NPV of 98.7% (98.6%-98.8%). The dipstick positive predictive value was significantly greater than combined urinalysis (66.8% [66.2%-67.4%] vs 51.2% [50.6%-51.8%]). These data suggest 8 febrile infants would be predicted to have a false-positive combined urinalysis for every 1 infant with UTI initially missed by dipstick screening.


CONCLUSIONS
Urine dipstick testing compares favorably with both microscopy and combined urinalysis in febrile infants aged 1 to 90 days. The urine dipstick test may be an adequate stand-alone screen for UTI in febrile infants while awaiting urine culture results.
Department of Pediatrics and Institute for Health Care Delivery Research and eric.glissmeyer@hsc.utah.edu.
Eric W
EW
Glissmeyer
Department of Pediatrics and Pediatric Clinical Program, Intermountain Healthcare, Salt Lake City, Utah.
E Kent
EK
Korgenski
Department of Pediatrics and Pediatric Clinical Program, Intermountain Healthcare, Salt Lake City, Utah.
Jacob
J
Wilkes
Department of Pediatrics and Pediatric Clinical Program, Intermountain Healthcare, Salt Lake City, Utah.
Jeff E
JE
Schunk
Department of Pediatrics and.
Xiaoming
X
Sheng
Department of Pediatrics and.
Anne J
AJ
Blaschke
Department of Pediatrics and Research Enterprise, University of Utah, Salt Lake City, Utah; and.
Carrie L
CL
Byington
D001437:Bacteriuria / Q000175:diagnosis* / Q000382:microbiology; D003937:Diagnosis, Differential; D005260:Female; D005335:Fever of Unknown Origin / Q000209:etiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening; D008853:Microscopy; D011237:Predictive Value of Tests; D016482:Urinalysis / Q000379:methods*; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000382:microbiology
infant; leukocyte esterase; newborn; nitrites; predictive value of tests; reagent strips; urinalysis; urinary tract infection; utilization