Alternative external quality assessment programme for SARS-CoV-2 serology: quality in pandemic times

For the control of COVID-19 pandemic it is essential to have reliable tests for the detection of antibodies against severe acute respiratory syndrome due to coronavirus 2 (SARS-CoV-2). For this reason, the Serology Laboratory and the Residence of Clinical Biochemistry of Hospital Garrahan developed the first Alternative Pilot Programme for external quality assessment for SARS-CoV-2 serology in Argentina, aimed at comparatively evaluating the performance of the available methods of the participants using different anti-SARS-CoV tests in order to ensure reliable and clinically useful results. The scheme consisted of 4 deliveries with 5 samples each throughout the second semester of 2020, with variable reactivity against SARS-CoV-2 in which total antibodies, IgG and IgM were evaluated. Twenty one public and private laboratories participated in the Province and the City of Buenos Aires for free. The methodology applied and the results were informed. At the end of each delivery, individual reports were sent and a final global report was made with the total results of the cycle. A total of 643 results were reported, 239 for anti-SARS-CoV-2 IgM, 365 for IgG and 39 for total antibodies. There was greater agreement in the anti-SARS-CoV-2 IgG methodologies than in IgM. ELISA/COVIDAR was the most frequently used methodology for IgG and ELFA/bioM & eacute;rieux for IgM. The spectrum of methodologies was wide. The programme was useful to ensure the quality of the results, providing the participants with the necessary framework to issue reliable and harmonised results.