Medichecks uses the Roche Anti-SARS-CoV-2 S antibody test which has been CE-marked for use on capillary and venous blood samples. This test detects antibodies to the coronavirus spike protein which the virus uses to gain entry to the body’s cells. Roche reports that the test detected antibodies in 98.8% of confirmed coronavirus cases when the sample was taken at least 14 days after symptoms first developed. The test produced a negative result in 99.98% of samples from people who did not have the SARS-CoV-2 infection. The test checks for the presence of IgM and IgG antibodies, and will tell you the level of antibodies detected but not which type of antibody.
This test may not accurately detect antibodies in people who have compromised immune systems because their antibody response may be slower or weakened. This may affect the reported results above. These people may have immunodeficiency diseases, infections such as HIV, or be taking medications that suppress the immune system.
A negative result does not exclude a current infection particularly in those who have recently been exposed to SARS-CoV-2, or in those who currently have symptoms of COVID-19, because antibodies to the virus may not have reached detectable levels at this point.