Evaluating the Impact of a Urinalysis to Reflex Culture Process Change in the Emergency Department at a Veterans Affairs Hospital
Background: Although automated urine cultures (UCs) following urinalysis (UA) are often used in emergency departments (EDs) to identify urinary tract infections (UTIs), results are often reported as no organism growth or the growth of clinically insignificant organisms, leading to the overdetection and overtreatment of asymptomatic bacteriuria (ASB).
Methods: A process change was implemented at a US Department of Veterans Affairs medical center ED that automatically cancelled UCs if UAs had < 5 white blood cells per high-power field (WBC/HPF). An option for do not cancel (DNC) UC was available. Data were prospectively collected for 3 months postimplementation and included UA/UC results, presence of UTI symptoms, antibiotics prescribed, and health care utilization.
Results: Postintervention, 684 UAs (37.2%) were evaluated from ED visits. Postintervention, of 255 UAs, 95 (37.3%) were negative with UC cancelled, 95 (37.3%) were positive with UC processed, 43 (16.9%) were ordered as DNC, and 22 (8.6%) were ordered without a UC. UC processing despite a negative UA significantly decreased from 100% preintervention to 38.6% postintervention ( P < .001). Inappropriate prescribing of antibiotics for ASB was reduced from 10.2% preintervention to 1.9% postintervention (odds ratio = 0.17; P = .01). In patients with negative UA specimens, antibiotic prescribing decreased by 25.3% postintervention. No reports of outpatient, ED, or hospital visits for symptomatic UTI were found within 7 days of the initial UA postintervention.
Conclusions: The UA to reflex culture process change resulted in a significant reduction in processing of inappropriate UCs and unnecessary antibiotic use for ASB. There were no missed UTIs or other adverse patient outcomes.
In clinical practice, there is a natural tendency to reflexively prescribe antibiotics based on the results of a positive UC due to the hesitancy in ignoring these results, despite lack of a suspicion for a true infection. Leis and colleagues explored this in a proof-of-concept study evaluating the impact of discontinuing the routine reporting of positive UC results from noncatheterized inpatients and requesting clinicians to call the laboratory for results if a UTI was suspected.16 This intervention resulted in a statistically significant reduction in treatment of ASB in noncatheterized patients from 48 to 12% pre- and postintervention. Clinicians requested culture results only 14% of the time, and there were no adverse outcomes among untreated noncatheterized patients. More recently, a QI study conducted at a large community hospital in Toronto, Ontario, Canada, implemented a 2-step model of care for urine collection.17 UC was collected but only processed by the microbiology laboratory if the ED physicians deemed it necessary after clinical assessment.
After implementation, there was a decrease in the proportion of ED visits associated with processed UC (from 6.0% to 4.7% of visits per week; P < .001), ED visits associated with callbacks for processing UC (1.8% to 1.1% of visits per month; P < .001), and antimicrobial prescriptions for urinary symptoms among hospitalized patients (from 20.6% to 10.9%; P < .001). Equally important, despite the 937 cases in which urine was collected but cultures were not processed, no evidence of untreated UTIs was identified.17
The results from the present study similarly demonstrate minimal concern for potentially undertreating these patients. As seen in the subgroup of patients included in the positive UA group, which did not meet criteria for positive UA per protocol (n = 29), only 2 of the subsequent cultures were positive, of which only 1 patient required antibiotic therapy based on the clinical presentation. In addition, in the group of negative UAs with subsequent cancellation of the UC, there were no found reports of outpatient visits, ED visits, or hospital admissions within 7 days of the initial UA for UTI-related symptoms.
Limitations
This single-center, pre-post QI study was not without limitations. Manual chart reviews were required, and accuracy of information was dependent on clinician documentation and assessment of UTI-related symptoms. The population studied was predominately older males; thus, results may not be applicable to females or young adults. Additionally, recognition of a negative UA and subsequent cancellation of the UC was dependent on laboratory personnel. As noted in the patient group with a positive UA, some of these UAs were negative and may have been overlooked; therefore, subsequent UCs were inappropriately processed. However, this occurred infrequently and confirmed the low probability of true UTI in the setting of a negative UA. Follow-up for UTI-related symptoms may not have been captured if a patient had presented to an outside facility. Last, definitions of a positive UA differed slightly between the pre- and postintervention groups. The preintervention study defined a positive UA as a WBC count > 5 WBC/HPF and positive leukocyte esterase, whereas the present study defined a positive UA with a WBC count > 5. This may have resulted in an overestimation of positive UA in the postintervention group.
Conclusions
Better selective use of UC testing may improve stewardship resources and reduce costs impacting both ED and clinical laboratories. Furthermore, benefits can include a reduction in the use of time and resources required to collect samples for culture, use of test supplies, the time and effort required to process the large number of negative cultures, and resources devoted to the follow-up of these ED culture results. The described UA to reflex culture process change demonstrated a significant reduction in the processing of inappropriate UC and unnecessary antibiotics for ASB. There were no missed UTIs or other adverse patient outcomes noted. This process change has been implemented in all departments at the Hines VA and additional data will be collected to ensure consistent outcomes.
