Performance Evaluation of HB&L Uroquattro System for Urinary Tract Infection Rapid Screening.

BACKGROUND: Precise and rapid pathogen identification is key in urinary tract infection (UTI) treatment. A negative rapid urine culture screening result provides critical information for clinical decision-making. Though the urine culture is the "gold standard" for UTI diagnosis, it usually takes about 48 hours to determine that bacteria aren't present in the culture. The HB&L uroquattro system (Aifax, Italy), formerly URO-QUICK, which can rule out the negative samples within 4 hours, should be evaluated for routine diagnostics. To this aim, this study evaluated the diagnostic accuracy of the HB&L uroquattro system by comparing with the gold standard conventional culture method and exploring the application value in clinical setting.

METHODS: A total of 300 midstream urine samples were both cultured by routine method and HB&L uroquattro system in this study. Diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values were calculated. To evaluate the relationship between turbidity and report time, the urine samples were measured as McFarland turbidity (following the method of reference [13]) before being loaded on the machine. The instrument provided HB&L turbidity when sample was reported as positive.

RESULTS: In total, 218 (73%) urine samples showed identical results by both methods, only 13 (6%) samples were misclassified as sterile by HB&L uroquattro system. At 102 CFU/mL, HB&L has the highest sensitivity with 91.67% (95% CI: 86.27% - 95.07%). At 105 CFU/mL, HB&L has the highest specificity with 97.22% (95% CI: 93.08% - 98.91%). McFarland turbidity showed a stronger correlation with report time.

CONCLUSIONS: The HB&L uroquattro system can give reliable urine microbiological results within 4 hours in appropriate clinic settings.