Evaluation of commercially available immuno‐magnetic agglutination in comparison to enzyme‐linked immunosorbent assays for rapid point‐of‐care diagnostics of COVID‐19

Moeller, Maria E.; Fock, Jeppe; Pah, Pearlyn; Veras, Antia De La C.; Bade, Melanie; Donolato, Marco; Israelsen, Simone B.; Eugen‐Olsen, Jesper; Benfield, Thomas; Engsig, Frederik N.

INTRODUCTION: Coronavirus disease 2019 (COVID‐19) is caused by Severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2). Fast, accurate, and simple blood‐based assays for quantification of anti‐SARS‐CoV‐2 antibodies are urgently needed to identify infected individuals and keep track of the spread of disease. METHODS: The study included 33 plasma samples from 20 individuals with confirmed COVID‐19 by real‐time reverse‐transcriptase polymerase chain reaction and 40 non‐COVID‐19 plasma samples. Anti‐SARS‐CoV‐2 immunoglobulin M (IgM)/immunoglobulin A (IgA) or immunoglobulin G (IgG) antibodies were detected by a microfluidic quantitative immunomagnetic assay (IMA) (ViroTrack Sero COVID IgM + IgA/IgG Ab, Blusense Diagnostics) and compared to an enzyme‐linked immunosorbent assay (ELISA) (EuroImmun Medizinische Labordiagnostika). RESULTS: Of the 33 plasma samples from the COVID‐19 patients, 28 were positive for IgA/IgM or IgG by IMA and 29 samples were positive by ELISA. Sensitivity for only one sample per patient was 68% for IgA + IgM and 75% IgG by IMA and 80% by ELISA. For samples collected 14 days after symptom onset, the sensitivity of both IMA and ELISA was around 91%. The specificity of the IMA reached 100% compared to 95% for ELISA IgA and 97.5% for ELISA IgG. CONCLUSION: IMA for COVID‐19 is a rapid simple‐to‐use point‐of‐care test with sensitivity and specificity similar to a commercial ELISA.