Photo Credit: Iryna Inshyna

A point-of-care urine dipstick test accurately diagnoses urinary tract infection (UTI) in febrile infants aged 2 to 6 months, according to a study published online in Pediatrics.

“Clinicians can use urine dipstick results (combining leukocyte esterase and nitrite) to guide initial antibiotic decisions while awaiting urine culture results,” Kathryn M. Hunt, MD, and colleagues wrote.

The study compared the accuracy of a urine dipstick test with urinalysis for identifying UTI in previously healthy infants. The babies presented to the emergency departments at five children’s hospitals in the United States with a temperature greater than or equal to 38.0 °C (100.4 °F) and had a urine culture obtained during the visit.

“We defined a UTI with a urine culture growing greater than or equal to 50,000 colony-forming units per milliliter of a single bacterial uropathogen,” the researchers explained. “Using receiver operator characteristic (ROC) curve analysis to select the optimal urine white blood cell (WBC) cut point, we compared positive urine dipstick (≥1+ leukocyte esterase or positive nitrite) to dichotomized urine WBC count for the diagnosis of UTI.”

Urine cultures were performed in a total of 9,387 febrile infants. Among them, 11% had a UTI. Infants with UTI were older, more often female, and had higher peak temperatures. The most common pathogen was Escherichia coli, which was identified in 88.4%.

Implications for Clinical Settings

ROC curve analysis indicated the optimal urine WBC cutoff was seven or more cells per high-power field (HPF).

“A positive urine dipstick had a higher sensitivity (90.2%; 95% CI, 88.1%–92.1%; difference 6.4%, 95% CI, 3.8%–8.9%) and specificity (92.6%; 95% CI, 91.9%–93.2%; difference 5.6%, 95% CI, 4.7%–6.6%), when compared with urine WBC count greater than or equal to 7 cells per HPF (sensitivity 83.9%; 95% CI, 81.3%–86.2%; specificity 87.0%; 95% CI, 85.9%–88.0%),” the researchers wrote.

The findings carry implications for faster diagnostic decision-making, lowered costs, and greater patient satisfaction.

“Point-of-care testing can be done in a variety of clinical settings, including primary care clinics and urgent care centers, which often lack real-time access to diagnostic laboratories …” Dr. Hunt and colleagues wrote. “Urine dipstick use may increase the speed at which clinicians can make clinical decisions, thus potentially decreasing length of stay, alleviating overcrowding, strengthening quality of care, and increasing patient satisfaction.”