Optimizing reflex urine cultures: Using a population-specific approach to diagnostic stewardship

• DOI: 10.1017/ice.2022.315
• Publication Date: 2023-01-10T07:57:52Z
• Authors: Sonali D. Advani; Nicholas A. Turner; Kenneth E. Schmader; Rebekah H. Wrenn; Rebekah W. Moehring; Christopher R. Po...; Valerie M. Vaughn; Deverick J. Anderson
• Keywords: Bacteriuria; Urinalysis; Urine; 6. Clean water; 3. Good health; 03 medical and health sciences; Urinary Tract Infections; Reflex; Humans; Female; Pyuria; 0305 other medical science; Retrospective Studies

AbstractBackground:Clinicians and laboratories routinely use urinalysis (UA) parameters to determine whether antimicrobial treatment and/or urine cultures are needed. Yet the performance of individual UA parameters and common thresholds for action are not well defined and may vary across different patient populations.Methods:In this retrospective cohort study, we included all encounters with UAs ordered 24 hours prior to a urine culture between 2015 and 2020 at 3 North Carolina hospitals. We evaluated the performance of relevant UA parameters as potential outcome predictors, including sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). We also combined 18 different UA criteria and used receiver operating curves to identify the 5 best-performing models for predicting significant bacteriuria (≥100,000 colony-forming units of bacteria/mL).Results:In 221,933 encounters during the 6-year study period, no single UA parameter had both high sensitivity and high specificity in predicting bacteriuria. Absence of leukocyte esterase and pyuria had a high NPV for significant bacteriuria. Combined UA parameters did not perform better than pyuria alone with regard to NPV. The high NPV ≥0.90 of pyuria was maintained among most patient subgroups except females aged ≥65 years and patients with indwelling catheters.Conclusion:When used as a part of a diagnostic workup, UA parameters should be leveraged for their NPV instead of sensitivity. Because many laboratories and hospitals use reflex urine culture algorithms, their workflow should include clinical decision support and or education to target symptomatic patients and focus on populations where absence of pyuria has high NPV.