2025 Southeastern Residency Conference

Title: Evaluation of Impact of Urinalysis Reflex to Culture Criteria Implementation
Authors: Morgan Vincent, Courtney Jackson, Emily Sinclair, Jeremy Frens, Cynthia Snider, Jeffrey Hatcher, Trung Vu, John Rizzo, Mike Boyer, Danielle Mahaffey, Andre Harvin 

Background/Purpose: Urinary tract infections (UTIs) are among the most common bacterial infections in both inpatient and outpatient settings, representing a significant burden on healthcare systems. Effective diagnosis and management of UTIs is imperative to improve patient outcomes. Although urinary symptoms are the mainstay of diagnosing UTIs, a urinalysis is often used as a supporting diagnostic tool. However, contamination, recent antibiotic use, and other acute illnesses can impact urinalysis and can be misleading, resulting in false-positives or false-negatives. Often, urine cultures are ordered despite the recognition of these drawbacks or lack of urinary symptoms, leading to unnecessary antibiotic prescribing. A recent cohort study conducted by Petty et al 2020 found that in 2,461 patients diagnosed with asymptomatic bacteriuria, 74.4% of patients received antibiotics and 80% of patients had urine cultures ordered. Previous literature also suggests urinalyses with WBC >5/hpf plus positive nitrites have a positive predictive value of 98% for positive culture. Additionally, the implementation of urinalysis reflex criteria reduces rates of urine culturing relative to control sites without increasing the rate of gram-negative blood stream infections. This project aims to analyze the effect of implementing reflex to urine culture criteria to reduce rates of unnecessary urine culturing in a community teaching hospital. 
 
Methodology: This multicenter, IRB-approved pre-post quality improvement study evaluated the impact of implementing conditional urinalysis reflex to culture criteria in an acute care setting. The reflex to culture was automatically cancelled if the urinalysis showed WBC <10/hpf or squamous epithelial cells >5/hpf. Patients were included if they had a urinalysis with urine culture ordered within the pre-intervention period November to December 2023 or a reflex order in the post-intervention period November to December 2024. Exclusion criteria were age less than 18, pregnancy, neutropenia (WBC <1.5 K/µL or ANC <1000/µL) or indwelling urinary catheter for greater than 5 days.  The primary outcome was proportion of urine cultures meeting reflex criteria. Secondary outcomes included days of ceftriaxone therapy, number of total urine cultures for cost-savings analysis, number of urine cultures ordered outside the reflex order, and number of patients with gram-negative bacteremia. A subgroup analysis of reflex orders by site (Emergency Department and Inpatient) pre-intervention and post-intervention was also conducted. The primary outcome was assessed via Chi-square analysis and secondary outcome were assessed with Wilcoxon rank sum or descriptive statistics. 
 
Results: A significant difference was found in all cultures that met reflex criteria in the pre- and post-intervention groups, with 53% of cultures meeting reflex criteria in the post-intervention group compared to 28% in the pre-intervention group (p<0.001). There was no difference between the pre- and post-intervention groups in overall cost savings, total number of ceftriaxone days (4969 vs 5613, p = 0.06), or in total incidence of gram-negative bacteremia (153 vs 156, p = 0.68). Sixty eight percent (3901/4517) of the total cultures post-intervention were ordered outside of the reflex order. In a subgroup analysis of reflex orders by location, the post intervention group had significantly more cultures that met reflex criteria than the pre-intervention group in either the Emergency Department or Inpatient locations.  
 
Conclusions: Implementation of a reflex to urine culture criteria significantly improved the overall quality of urine cultures collected but did not cause a difference in cost savings, total number of ceftriaxone days, or incidence of gram-negative bacteremia. 

Presentation Objective: Evaluate the Impact of Urinalysis Reflex to Culture Criteria Implementation at a Community Teaching Hospital
Self Assessment Question: True/False: A urinalysis is considered positive if it contains >10 WBCs /hpf and <5 SQCs/hpf.