Rapid point-of-care testing for urinary tract infections: diagnostic accuracy and clinical impact.

Abstract

Background: The PA-100 AST system (Sysmex®) is a point-of-care test (POCT) that tests for bacteria in urine samples using a fixed threshold and performs antimicrobial susceptibility testing (AST) within 45 minutes.

Aim: To evaluate the diagnostic accuracy and perceived clinical utility of the PA-100 AST for diagnosing uncomplicated urinary tract infection (uUTI) in people assigned female at birth.

Design & setting: Prospective multicentre diagnostic accuracy study in four primary care practices in Germany.

Method: Urine samples from adult female patients with uUTI symptoms were tested using the PA-100 AST (index test) and standard laboratory urine culture (reference standard). General practitioners reported the perceived clinical utility.

Results: Data from 109 patients (median age 59 years, interquartile range: 43 - 72) were analysed. Bacteriuria prevalence was 63%. For bacterial detection, sensitivity was 86% (95% CI 67-88) and specificity 80% (95% CI 63-93). Positive and negative predictive values were 88% (95% CI 80-96) and 76% (95% CI 46-77), respectively. For AST, overall categorical agreement across uUTI antibiotics was 84% for ciprofloxacin, 87% for fosfomycin, 94% for trimethoprim and 95% for nitrofurantoin. The overall sensitivity for identifying non-susceptible pathogens was 74% (11/15), but was particularly low for ciprofloxacin (40%, 2/5). Among the 15 resistant isolates, the PA-100 AST misclassified four (27%) as susceptible. GPs reported that results influenced prescribing in 25% of consultations, equally split between initiating antibiotics after initially withholding ("step-up") and withholding after initially considering treatment ("step-down"). GPs reported that using the PA-100 AST improved communication, increased diagnostic confidence, and that the test could be readily integrated into routine workflow.

Conclusion: The PA-100 AST showed moderate diagnostic accuracy and may support management of suspected uUTI in primary care. However, its relatively low negative predictive value observed in our study population limits its ability to rule out bacteriuria. The test had a modest impact on prescribing decisions but further research is needed to determine its effectiveness in optimizing antibiotic use.