How Sensitive are Dipstick Urinalysis and Microscopy in Making Diagnosis of Urinary Tract Infection in Children?

Abstract

Background: Urinary tract infection (UTI) is a common reason for referral to the emergency department (ED) especially in unwell infants. Upper UTIs are particularly at risk of signifcant complications later in life. Rapid dipstick urinalysis and microscopy are often used in unwell children as a screening tool to guide early diagnosis and treatment. This study aims to evaluate the sensitivity of dipstick urinalysis and microscopy in the diagnosis of UTI.

Methods: A retrospective review of children aged 16 years and below with positive urine culture (UC) over a 3‑year period was done. The results of urine dipstick and microscopy were compared with the positive UC and sensitivities calculated.

Results: Dipstick urinalysis and microscopy of 262 children were studied. Female‑to -male ratio of 1.8:1. Median age was 0.79 (range: 0.02–15.95) years. The sensitivity of nitrite, blood, and leukocyte esterase (LE) were 0.54, 0.74, and 0.86 (95% confdence interval [CI] = 0.46–0.62, 0.68–0.80, and 0.82–0.91), respectively. The sensitivity of pyuria of ≥100 cells/mm3 was 0.92 (95%
CI = 0.89–0.95). The presence of any of the 3 dipstick parameters increased the sensitivity to 0.97 (95% CI = 0.95–0.99). The lowest sensitivity 0.49 (95% CI = 0.40–0.58) was found with combined positive LE and nitrite. There was a signifcant comparison between positive LE dipstick test and pyuria (P = 0.000004).

Conclusions: Dipstick urinalysis may not be reliable in ruling out UTI in children. However, considering both positive dipstick and pyuria will be more useful in
making the diagnosis.

Keywords: Mass screening, microscopy, pyuria, urinalysis, urinary tract infections