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Positive predictive value of urine analysis with reflex criteria at a large community hospital
Chelsey Axelrod1, Jessica Cobian2, Jennifer Montero2
1St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, 18015, USA. chelsaxel@gmail.com.
Introduction And Hypothesis:
Urine 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.
Methods:
This 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.
Results:
The 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.
Conclusions:
Further optimization is needed for URTC criteria and the appropriateness of ordering UAs to reduce operational laboratory costs and inappropriate antibiotic treatment.
Insights
The positive predictive value of urine analysis with reflex to culture (URTC) for diagnosing urinary tract infections (UTIs) was 58%. Current URTC criteria require optimization to improve accuracy and reduce unnecessary antibiotic use.
Area of Science:
- Clinical diagnostics
- Microbiology
- Laboratory medicine
Background:
- Urine analysis with reflex to culture (URTC) aids in diagnosing urinary tract infections (UTIs).
- Current criteria for reflexing urine analysis (UA) to culture lack evidence-based guidance, leading to variability.
- The positive predictive value (PPV) of URTC varies across studies.
Purpose of the Study:
- To evaluate the predictive accuracy of established URTC criteria for urine culture positivity.
- To determine the PPV of specific URTC criteria (moderate/more WBCs, few/more bacteria, few/no epithelial cells).
Main Methods:
- Retrospective, single-center study of 350 adult patients at a community hospital.
- Analysis of URTC orders from October 2020 using electronic health records.
- Statistical analysis included descriptive statistics, Mann-Whitney U test, and logistic regression.
Main Results:
- The overall PPV of the URTC criteria was 58%.
- Factors predicting negative urine cultures included younger patient age, male sex, and emergency department visits for fall/syncope or other non-specific reasons.
Conclusions:
- The current URTC criteria demonstrate suboptimal predictive value for urine culture positivity.
- Optimization of URTC criteria is necessary to reduce laboratory costs and prevent inappropriate antibiotic prescribing.
- Further research is needed to refine UA ordering appropriateness.
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