Universal SARS-CoV-2 Testing of Emergency Department Admissions Increases Emergency Department Length of Stay

ABSTRACT Background Our institution experienced both a change in SARS-CoV-2 testing policy as well as substantial changes in local COVID-19 prevalence allowing for a unique examination of the relationship between SARS-CoV-2 testing and ED length of stay (LOS). Methods An observational interrupted time series of all patients admitted to an academic health system between March 15, 2020 and September 30, 2020. Given testing limitations from March 15 to April 24, all patients receiving a SARS-CoV-2 test were symptomatic. On April 24, testing was expanded to all ED admissions. The primary and secondary outcome was ED LOS and number needed to test (NNT) to obtain a positive, respectively. Results A total of 70,856 patients were cared for in the EDs during the seven month period. The testing change increased admission LOS by 1.89 hours (SE 0.25, 95% CI: 1.39, 2.38). The NNT was 2.5 patients and was highest yield on April 1, 2020 when the state positivity rate was 39.7%, however the NNT exceeded 170 patients by Sept 1, 2020 at which point the state positivity rate was 0.5%. Discussion While universal SARS-CoV-2 testing of ED admissions may meaningfully support mitigation and containment efforts, the clinical cost of testing all admissions amidst low community positivity is notable. In our system, universal ED SARS-CoV-2 testing was associated with a 24% increase in admission LOS alongside the detection of only one positive case every other day. Given the known harms and risks of ED boarding and crowding, solutions must be developed to support regular operational flow while balancing infection prevention needs.