NHAMCS ED Urinalysis, Blood Testing, and Length of Visit 2006-2015

BACKGROUND: Despite the popular conception that ordering a urinalysis causes a significant increase in Emergency Department (ED) length of visit (LOV), there is little research on its actual impact . OBJECTIVES: This study investigated the quantitative impact of obtaining the results of a urinalysis, compared to the quantitative impact of obtaining the results of any laboratory testing of blood (“blood testing”), upon ED LOV in the National Hospital Ambulatory Medical Care Survey – Emergency Department [NHAMCS-ED] dataset. METHODS: The NHAMCS - ED dataset was queried from 2006 – 2015, comparing LOS in visits where urinalysis was ordered, blood testing was ordered, both were ordered, or neither. RESULTS: 1,232,279,000 ED visits with LOV data were found in the study period. Urinalysis was performed in 24.2% of visits, Blood testing in 36.7%, both in 18.2%, and none in 57.4%. Median LOV was 153 minutes. No blood or urine testing had a median LOV of 109, Urinalysis only 161 minutes, Blood testing only 221 minutes, and both 250 minutes. CONCLUSION: Urinalysis does increase LOV, but blood testing increases it more, with additive effects when both are ordered.