Impact of Reflex Algorithms on Urine Culture Utilization

Urine culture is the gold standard for the diagnosis of urinary tract infection (UTI), one of the most common causes of bacterial infection. As such, urine specimens are responsible for a major share of the workload in clinical microbiology laboratories. The inclusion of metrics, such as the catheter-associated UTI (CAUTI) rate, that factor into hospital reimbursements and concerns surrounding the attrition of clinical laboratory personnel have prompted scrutiny of urine culture utilization in many organizations. One strategy to improve urine culture management is the institution of urine reflex algorithms that restrict urine culture to specimens with evidence of inflammation on urinalysis. The high negative predictive value of indicators of pyuria and bacteriuria on urinalysis are useful to rule out UTI and thus the need for culture. Data from several studies support the notion that use of reflex criteria reduces urine culture utilization. However, few studies have examined the impact of reflex algorithms on CAUTI rates and antibiotic use. This article provides an overview of the laboratory diagnosis of urinary tract infections with a focus on the utility of urinalysis and reflex testing algorithms.