Antibody tests are intended as aids in identifying individuals with an adaptive immune response to COVID-19, indicating recent or prior infection. It can be useful in providing evidence of an immune response over time and may benefit people at high-risk for being infected or for severe outcomes. Results are for the detection of SARS-CoV-2 antibodies.
IgG and IgM antibodies to SARS-CoV-2 are generally detectable in blood several days after initial infection, although the duration of time antibodies are present post-infection is not well characterized.
At this time, it is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity. Individuals may have detectable virus present for several weeks following seroconversion. Negative results do not preclude acute SARS-CoV-2 infection. If acute infection is suspected, molecular testing for SARS-CoV-2 is necessary. The tests should not be used to diagnose acute SARS-CoV-2 infection. False-positive results for the test may occur due to cross-reactivity from pre-existing antibodies or other possible causes.
The sensitivity of the IgM test early after infection is unknown. Due to the risk of false-positive results, confirmation of positive results should be considered using a second, different IgM assay or an IgG assay. Samples should only be tested for IgM from individuals with 15 days to 30 days post-symptom onset. SARS-CoV-2 antibody negative samples collected 15 days or more post-symptom onset should be reflexed to a test that detects and reports SARS-CoV-2 IgG.
- The antibody tests have not been FDA cleared or approved
- The antibody tests have been authorized by FDA under an Emergency Use Authorization (EUA) for use by authorized laboratories
- The antibody tests have been authorized only for detecting antibodies against SARS-CoV-2, not for any other viruses or pathogens
- The SARS-CoV-2 Total Antibody, Spike, Semi-Quantitative test has been authorized by FDA under an EUA for use by laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. 263a, that meet requirements to perform high complexity tests
- The IgM serology test component has been authorized only for the detection of IgM antibodies against SARS-CoV-2, not for any other viruses or pathogens
- These tests are only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostic tests for detection and/or diagnosis of COVID-19 under Section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act, 21 U.S.C § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner