Positive predictive value of urine analysis with reflex criteria at a large community hospital

Introduction and hypothesisUrine analysis with reflex to culture (URTC) is employed as a diagnostic aid for urinary tract infections (UTIs). Criteria utilized to determine whether a urine analysis (UA) will reflex varies owing to a lack of evidence-based guidance. Positive predictive value (PPV) of URTC varies across studies. The URTC criteria in this study included moderate or more white blood cells (> 5 high-power field [HPF]), few or more bacteria (> 1 HPF), and few or no epithelial cells (< 3 HPF). The purpose of this study was to determine the extent to which URTC predicts culture positivity.MethodsThis study was a single-center, retrospective evaluation at a large community hospital. A report of URTC ordered in adults in October 2020 was generated from the hospital's electronic database. The primary outcome was to determine the PPV of URTC criteria. The secondary outcome was to examine the differences in microscopic UA results between culture-positive and culture-negative urine. A total of 350 patients were included for analysis. The data was analyzed through descriptive statistics, Mann-Whitney U test, and multivariate logistic regression.ResultsThe results showed a PPV of 58%. Variables predicting negative culture included younger patients, males, and a reason for the visit to the emergency department of a fall/syncope or other.ConclusionsFurther optimization is needed for URTC criteria and the appropriateness of ordering UAs to reduce operational laboratory costs and inappropriate antibiotic treatment.

Automated summary

Urine analysis with reflex to culture (URTC) is used as a diagnostic aid for urinary tract infections (UTIs), but there is a lack of evidence-based guidance. This study aimed to determine the accuracy of URTC in predicting culture positivity.