SARS-CoV-2 antibody testing is a major part of managing the spread of COVID-19,1 and Quest Diagnostics offers a full complement of antibody serology testing.
These tests are intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. 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.
A semi-quantitative spike antibody test can be useful in providing evidence of an immune response over time.
- This may be especially valuable insight for individuals enrolled in ongoing clinical trials and vulnerable patient populations
- Results obtained with this assay may not be used interchangeably with values obtained with different manufacturers’ test methods2
- The results of this semi-quantitative test should not be interpreted as an indication or degree of immunity or protection from reinfection
The antibody tests currently offered by Quest Diagnostics have been authorized by FDA under an Emergency Use Authorization (EUA) for use by authorized laboratories3
- SARS-CoV-2 Antibody (IgG), Spike, Semi-Quantitative (test code 34499)
- SARS-CoV-2 Total Antibody, Spike, Semi-Quantitative (test code 39820)
- SARS-CoV-2 Antibody (IgG), Nucleocapsid, Qualitative (a component of the IgG/IgM panel, test code 31672) (test code 39749)
- SARS-CoV-2 Serology (COVID-19) Antibodies (IgG, IgM), Immunoassay (test code 31672)
All antibody testing must be ordered by a physician. Patients may make an appointment at a Quest Patient Service Center for these tests.