IFCC Interim Guidelines on Serological Testing of Antibodies against SARS-CoV-2

Abstract

Serological testing for the detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as an important component of the clinical management of patients with coronavirus disease 2019 (COVID-19) as well as the epidemiological assessment of SARS-CoV-2 exposure worldwide. In addition to molecular testing for the detection of SARS-CoV-2 infection, clinical laboratories have also needed to increase testing capacity to include serological evaluation of patients with suspected or known COVID-19. While regulatory approved serological immunoassays are now widely available from diagnostic manufacturers globally, there is significant debate regarding the clinical utility of these tests, as well as their clinical and analytical performance requirements prior to application. This document by the International Federation for Clinical Chemistry and Laboratory Medicine (IFCC) Taskforce on COVID-19 provides interim guidance on: (A) clinical indications and target populations, (B) assay selection, (C) assay evaluation, and (D) test interpretation and limitations for serological testing of antibodies against SARS-CoV-2 infection. These evidence-based recommendations will provide practical guidance to clinical laboratories in the selection, verification, and implementation of serological assays and are of the utmost importance as we expand our pandemic response from initial case tracing and containment to mitigation strategies to minimize resurgence and further morbidity and mortality.

An Original ELISA-Based Multiplex Method for the Simultaneous Detection of 5 SARS-CoV-2 IgG Antibodies Directed against Different Antigens

“…The detection of anti-SARS-CoV-2 antibodies represents an additional method for the diagnosis of COVID-19 [ 4 , 6 ]. Serological assays serve as an adjunction test in patients with symptoms suggestive of COVID-19 (i.e., >14 days since symptom onset) but with a negative rRT-PCR result [ 7 , 8 ]. Use of serological testing to evaluate seroprevalence, to identify convalescent plasma donors, to monitor herd immunity and for risk predictions have also been proposed [ 3 , 7 ].…”

Performance of two rapid point of care SARS-COV-2 antibody assays against laboratory-based automated chemiluminescent immunoassays for SARS-COV-2 IG-G, IG-M and total antibodies

“…LFIAs since then continue to have sensitivities that can range from 22% to 60.9% [ 11 , 12 ]. Therefore, the recent IFCC guidelines [ 13 ] on serological testing for SARS-CoV-2 recommends follow up with a laboratory assay for patients with a high suspicion of infection even when negative POCT results are encountered.…”

Guidelines on newly identified limitations of diagnostic tools for COVID‐19 and consequences

“…In COVID‐19 antibody test, the blood sample is examined for the detection of antibodies against SARS‐CoV2 32 . Typically, subjects with COVID‐19 infection develop antibodies in 1–3 weeks post symptoms 32 .…”

“…In COVID‐19 antibody test, the blood sample is examined for the detection of antibodies against SARS‐CoV2 32 . Typically, subjects with COVID‐19 infection develop antibodies in 1–3 weeks post symptoms 32 . Severe symptoms usually manifest higher titer of antibodies in comparison to the moderate symptoms or without symptoms in infected subjects 33 .…”