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

Ghofrani, M.; Casas, M. T.; Pelz, R. K.; Kroll, C.; Blum, N.; Foster, S. D.

Objectives: We 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. Methods: Assuming 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). Results: During 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%]. Conclusions: Based 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.