Effecting the culture: Impact of changing urinalysis with reflex to culture criteria on culture rates and outcomes.

OBJECTIVE: To evaluate the impact of changes to urinalysis with reflex to culture (UARC) reflex criteria on culture performance and clinical decision outcomes. DESIGN: Retrospective study utilizing interrupted time series analysis from December 2018 to November 2020. Primary outcomes were measures of culture performance. Secondary outcomes were rates of antimicrobial prescription for suspected urinary tract infection (UTI) and catheter-associated urinary tract infection (CAUTI). We also assessed harmful events related to antimicrobial prescription for all causes and UTI, UTI symptoms, and sepsis. SETTING: A 415-bed, academic, tertiary-care, medical center. PATIENTS: Hospitalized adult patients with urine testing performed. INTERVENTION: UARC reflex criteria were changed on October 22, 2019, from ≥5×109/L white blood cells (WBCs) or trace leukocyte esterase or positive nitrite units on urinalysis to only ≥15×109/L WBCs. RESULTS: The study included 11,322 unique UARC tests. We detected a significant decrease in the rate of urine cultures performed from UARC after the intervention (32.5-8.7 cultures per 1,000 patient days; P < .001), with improved diagnostic efficacy (ie, culture positivity increased from 34.8% to 62.1%). CAUTI rates did not change. We detected a significant decrease in antimicrobial prescription rates (P = .05), this was primarily driven by preintervention changes. One case of sepsis occurred secondary to a missed UTI, and UTIs were rarely missed after the intervention. CONCLUSIONS: Implementation of a stricter UARC reflex criterion was associated with a decrease in culture rates with improved diagnostic efficacy without significant adverse events. Continued education is needed to change antimicrobial prescribing practices.

Impact of provider-selected indication requirement on urine test utilization and positivity.

Objective: To evaluate the impact of the addition of an indication specification requirement to isolated urine-culture ordering on testing utilization. Design: Retrospective study utilizing interrupted time series analysis with negative binomial regression. The preintervention period was October 1, 2018-November 11, 2019, and the postintervention period was November 12, 2019-October 31, 2020. The primary outcome was isolated culture rate per 1,000 patient days. Secondary outcomes were the proportion of all urine tests ordered as isolated urine culture and culture positivity. An exploratory analysis assessed the appropriateness of selected testing indications. Setting: A 415-bed, urban, academic medical center. Patients: Adult patients with urine testing performed during hospital admission. In total, 1,494 unique isolated urine-culture orders were included in the analysis. Interventions: On November 12, 2019, the laboratory order interface was changed to require the ordering provider to select an indication for isolated urine culture. Results: Isolated urine-culture rates did not significantly change after the intervention (11.2-7.8 cultures per 1,000 patient days; P = .17) nor did culture positivity (26.9% vs 26.8%). Most ordering providers left the indication for testing blank, and of those charts reviewed, 67% did not have a documented condition for which isolated urine culture was the most appropriate initial test. Conclusions: The addition of an order-specification requirement for isolated urine-culture testing did not significantly affect ordering practices. The test remains overused as the initial diagnostic evaluation for a suspected urinary tract infection. Further provider education and continued changes in provider workflow are needed to achieve lasting change in practice.