Screening for Urinary Tract Infection in Infants in the Emergency Department: Which Test Is Best?

Abstract

ABSTRACT. Objective. Comparison of rapid tests and screening strategies for detecting urinary tract infection (UTI) in infants.Methods. Cross-sectional study conducted in an urban tertiary care children's hospital emergency department and clinical laboratories of 3873 infants <2 years of age who had a urine culture obtained in the emergency department by urethral catheterization; results of urine dipstick tests for leukocyte esterase or nitrites, enhanced urinalysis (UA) (urine white blood cell count/mm 3 plus Gram stain), Gram stain alone, and dipstick plus microscopic UA (white blood cells and bacteria per high-powered field) compared with urine culture results (positive urine results defined as >10 4 colony-forming units per milliliter of urinary tract pathogen) for each sample. Cost comparison of 1) dipstick plus culture of all urine specimens versus 2) cell count ؎ Gram stain of urine, culture only those with positive results.Results. The enhanced UA was most sensitive at detecting UTI (94%; 95% confidence interval: 83,99), but had more false-positive results (16%) than the urine dipstick or Gram stain (3%). The most cost-effective strategy was to perform cultures on all infants and begin presumptive treatment on those whose dipstick had at least moderate (؉2) leukocyte esterase or positive nitrite at a cost of $3.70 per child. With this strategy, all infants with UTI were detected. If the enhanced UA was used to screen for when to send the urine for culture, 82% of cultures would be eliminated, but 4% to 6% of infants with UTI would be missed and the cost would be higher ($6.66 per child).Conclusion. No rapid test can detect all infants with UTI. Physicians should send urine for culture from all infants and begin presumptive treatment only on those with a significantly positive dipstick result. The enhanced UA is most sensitive for detecting UTI, but is less specific and more costly, and should be reserved for the neonate for whom a UTI should not be missed at first visit. Pediatrics 1998;101(6). URL: http://www.pediatrics. org/cgi/content/full/101/6/e1; urinalysis, Gram stain, dipstick, UTI, rapid screening, febrile infants.ABBREVIATIONS. UTI, urinary tract infection; ED, emergency department; WBC, white blood cells; UA, urinalysis; LE, leukocyte esterase; CFU/mL, colony forming units per milliliter; CI, confidence interval. R ecent research has indicated that the prevalence of urinary tract infection (UTI) in febrile young children in the emergency department (ED) is ϳ3% to 5%, and in some groups, as high as 30%.1,2 Additionally, recent use of nuclear renal scans has indicated that the majority of febrile young children with UTI have pyelonephritis, putting them at risk for renal scarring and the possible long-term sequelae of hypertension and chronic renal failure. [3][4][5] It is imperative that physicians identify these children to institute early treatment, work-up of their urinary tracts, and provide follow-up.Although there are several screening tests for UTI, there has been no prospective clinical...

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

“…Two of these were also included in our review, 177,178 and one was excluded 179 as it was based on secondary care. The review is therefore not considered further and this synthesis focuses instead on the eight primary studies.…”

Diagnostic Accuracy of the Urinalysis for Urinary Tract Infection in Infants &lt;3 Months of Age

“…[1][2][3][4][5][6] Because of this suboptimal sensitivity, the urine culture is considered to be the gold standard for the diagnosis of UTI. However, the findings of a positive urine culture in a patient with a negative UA also may reflect a false-positive urine culture due to asymptomatic bacteriuria or contamination.…”

Two-Step Process for ED UTI Screening in Febrile Young Children: Reducing Catheterization Rates

“…If the urine screened positive (moderate or large leukocyte esterase or presence of nitrites on urine dipstick), the child then underwent urethral catheterization for sterile urine culture, as urine specimens obtained by urine bag have an unacceptably high contamination rate. 9 Patients with positive dipstick results were started on prophylactic antibiotics initiated per ED pathway and patient outcomes and culture results were monitored closely through standard ED nurse practitioner follow-up practices.…”

“…Due to the predictive models' higher sensitivity than specificity for screening, 8 most urine samples will have a negative screen for pyuria or bacteriuria by urine dipstick or microscopy. 9 Historically, at the Children's Hospital of Philadelphia (CHOP), febrile children <24 months of age who were screened for UTI had urine obtained by urethral catheterization. Overall, 63% of febrile children in this age group were screened for UTI by urethral catheterization; screens were positive in only a small percentage of cases, with cultures positive in only 4.3%.…”