Rapid serological tests for SARS-CoV-2 IgG/IgM - not worth attention?

Krygier, Rafał; Stępień, Piotr M; Zarębska-Michaluk, Dorota

OBJECTIVES Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2) had spread worldwide since December 2019 and became a pandemic in March 2020. The diagnosis of an active infection is based on the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) from the nasopharyngeal swab specimen. The aim of the current analysis was to assess the usefulness of the rapid serological tests for diagnosing SARS-CoV-2 infections. MATERIAL AND METHODS The rapid serological tests detecting IgG/IgM antibodies for SARS-CoV-2 were voluntarily performed in asymptomatic employees of 2 companies. The examination was conducted at the date and time selected online by the study participants. The testing team consisted of 2 nurses collecting the samples and 1 doctor who interpreted the results. Each positive rapid test result was verified by an RT-PCR examination from a nasopharyngeal swab. The testing kits named Vazyme: 2019-nCoV IgG/IgM Detection Kit (Colloidal Gold-Based) were provided by the employer along with the manual and certificates. RESULTS The overall interest in testing among employees was below the employer's expectations and reached 30% and 20% in each of the 2 companies, respectively. A total of 516 participants were included in the analysis. Ten positive results of the rapid tests were documented, including 7 for IgM and 3 for IgG antibodies. No positive result was confirmed by the detection of the genetic material of the SARS-CoV-2 by the RT-PCR examination. CONCLUSIONS Herein, the authors demonstrated the uselessness of rapid serological tests performed in asymptomatic volunteers for diagnosing SARS-CoV-2 infections.