A brief performance evaluation and literature review of Abbott ID Now COVID-19 rapid molecular-based test

Aupaix, Antoine; Lazarova, Elena; Chemais, Monia

The qualitative ID Now COVID-19 assay combines claimed performance and ease of use that seem to position it as a reliable test for urgent patient management. However, the declared limit of detection (LOD) of 125 genome equivalents/mL is not confirmed by the published studies, which observed a range of LOD varying from 276 to 20.000 copies/mL. We decided to establish the LOD value on more robust basis using serial dilutions of a SARS-CoV-2 culture supernatant sample of defined concentration. Afterwards, we tested the analytical performances of the assay with 23 QCMD external quality control measurements. Hence, taking into consideration the additional dilution in the sample receiver cup, we found a lower 95% LOD of 64 copies/mL. For its intended use and with the new established LOD, ID Now COVID-19 proved to be a suitable test for the diagnosis of COVID-19 in contagious patients, as proposed by the latest Belgian recommendations.