A Systematic Review of the Accuracy and Reliability of Pyuria in Diagnosing Pediatric Urinary Tract Infections.

Urinary tract infections (UTIs) are among the most common bacterial infections during childhood. Early diagnosis and prompt treatment are necessary to prevent long-term sequelae. Pyuria, a key diagnostic marker for UTIs, is defined as the presence of ≥5 white blood cells per high-power field in urine obtained by centrifugation of urine and microscopic analysis. However, there is a debate around pyuria's role in UTI diagnosis, which highlights the need for a comprehensive evaluation of its diagnostic accuracy in pediatric settings. This study aims to evaluate the diagnostic accuracy of pyuria as a marker for UTIs in pediatric patients by analyzing the sensitivity, specificity, and various factors affecting the diagnostic performance of pyuria and the alignment of these findings with the current clinical guidelines of pediatric UTI management. A comprehensive search was conducted through the following electronic databases: PubMed, Central, and Science Direct. The articles underwent a two-phase filtration process: first by title and abstract and second by full text, conducted by two independent reviewers. Data was extracted using a Google form (Google LLC, Mountain View, CA, USA) covering study details, participant characteristics, biomarkers, and diagnostic methods. The methodological quality of the studies was assessed using the National Institutes of Health tool, and the detailed protocol is available on PROSPERO (CRD42023399392). Our search yielded 491 results, with 18 studies meeting the inclusion criteria. The mean age across the studies was 2.7 years, and the majority of patients were females. was the predominant pathogen, accounting for the infection in 5,696 (61%) out of 9,628 positive cultures. The included articles reported positive pyuria in 64% of the patients with positive cultures. It was found that the type of uropathogen, urinalysis techniques, urine concentration, patient demographics, and underlying congenital anomalies are among the factors that affect the diagnostic accuracy of pyuria. A generated receiver operating characteristic (ROC) revealed a higher diagnostic performance for pyuria with an area under the curve of (area under the curve (AUC)=0.793) compared to that of nitrite (AUC=0.671). Notably, pyuria was significantly associated with infections, although represented the majority of cases overall. Urinalysis techniques influenced the sensitivity and specificity of pyuria. Urinalysis performed by automated methods achieved sensitivity rates of 80% and specificity rates of 90%, whereas enhanced methods showed higher sensitivity at 84% and specificity at 94%. The absence of pyuria does not rule out the diagnosis of UTI among pediatric age groups who display symptoms of UTI. The onset of urinalysis in relation to fever onset, type of causative urinary pathogen, urine concentration, and other individual factors may lead to the absence of pyuria in the presence of true UTI. Further research is required to assess the diagnostic criteria for UTI among pediatrics and investigate the role of other biomarkers in accurately diagnosing UTI.