Comparison of Urine Dipstick, Microscopy, and Culture for the Detection of Bacteriuria in Children

Abstract

The authors compared dipstick tests for leukocyte esterase and nitrite and microscopic examination of urinary sediment with urine culture to assess whether the former tests could reliably rule out bacteriuria in specimens from children. The authors studied urine specimens from 1010 infants and children younger than age 18. Compared with culture at ≥105 colony forming units (cfu)/ml, the sensitivities of leukocyte esterase, nitrite, and microscopic examination of white blood cells (≥5 wbc/hpf) or bacteria (in at least moderate numbers) were 76 percent, 29 percent, 82 percent, and 80 percent, respectively. The specificities of the same tests were 81 percent, 99 percent, 81 percent, and 83 percent, respectively. Compared with culture at ≥104 cfu/ml, the sensitivities of the tests were 64 percent, 21 percent, 64 percent, and 59 percent; the specificities were 82 percent, 99 percent, 81 percent, and 83 percent, respectively. The negative predictive values of leukocyte esterase and microscopic examinations of urinary sediment for white blood cells and bacteria were all 95 percent (≥104 cfu/ml) or 98 percent (≥105 cfu/ml). The authors conclude that the leukocyte esterase test is as accurate as sediment microscopy in identifying urine specimens from infants and children harboring <10 4 or <105 cfu/ml.