Comparison of Enhanced and Manual Urinalysis for Detecting Urinary Tract Infections in Children

Abstract

Background: Urinary tract infections (UTIs) are among the most common bacterial infections in children. Urinalysis (UA) is a beneficial test for the preliminary diagnosis of UTIs. The presence of bacteriuria in UA can be determined by either an enhanced (using uncentrifuged Gram-stained specimens) or manual (using centrifuged specimens) technique. However, the diagnostic performance of enhanced UA is not well-established in childhood UTIs. Objectives: To assess the ability of enhanced and automated urinalysis to detect UTIs in children. Methods: This cross-sectional study was conducted on 191 children with the symptoms of UTI referred to Dr. Sheikh Hospital, Mashhad, Iran, from 2018 to 2019. Standard urinalysis, enhanced urinalysis, and quantitative urine culture were performed on specimens. A positive enhanced UA test was defined as ≥ 10 white blood cells per mL of urine and the presence of any bacteria per 10 high-power microscopic fields of a Gram-stained smear. A positive manual UA test was defined as ≥ 5 white blood cells per high-power field. The results of standard and enhanced UA were compared with urine culture findings to determine the accuracy of these two methods in detecting UTIs. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for each test. Results: The results showed that the prevalence of UTI was 23%. Enhanced UA retrieved a sensitivity of 97.7%, specificity of 93.1%, PPV of 81.1%, and NPV of 99.3% for detecting UTIs. In standard UA, sensitivity, specificity, PPV, and NPV were 90.9%, 80.7%, 57.1%, and 96.6% for pyuria, 56.8%, 98.6%, 92.5%, and 88.4% for the nitrite test, 72.7%, 94.5%, 80%, and 92% for the leukocyte esterase test, respectively. Conclusions: Enhanced UA had higher sensitivity, specificity, PPV, and NPV than standard UA.