Performance characteristics of the ID NOW COVID-19 assay: A regional health care system experience

Abstract ObjectivesWe compared the Abbott ID NOW COVID-19 point-of-care test (POCT) with polymerase chain reaction (PCR)-based methods to assess the claimed sensitivity and specificity of POCT and to optimize test utilization in our regional health care system. MethodsAssuming PCR to be the gold standard, we used a convenience sampling of mostly symptomatic COVID-19 suspect hospital patients who had already been tested for internal validation and guideline development purposes by both PCR and POCT to calculate the sensitivity and specificity of POCT with Clopper-Pearson 95% confidence intervals (CI). ResultsDuring the study period, 113 paired patient samples met eligibility criteria. The sensitivity of POCT in this population was calculated to be 94.1% [CI 71.31-99.85%] and the specificity was 99.0% [CI 94.33-99.97%]. ConclusionsBased on the lower sensitivity of POCT and the estimated prevalence of COVID-19 in our symptomatic and asymptomatic hospital patients, we recommend a two-pronged testing approach in which COVID-19 suspect patients are tested by the more sensitive PCR, while asymptomatic patients with a low pre-test probability of infection are tested with POCT supplemented by PCR confirmation of positive results. Furthermore, isolation decisions should not be based on POCT results alone.