Reactive test result: Indicates that only your initial antibody test was reactive for COVID-19 antibodies, while the second test that we performed was not reactive or was not able to be completed. This result means that you likely received the COVID-19 vaccine and did not have a COVID infection. Another less common explanation for a reactive result is that we were unable to complete both tests. It takes one to three weeks after the first dose of a COVID-19 vaccine to reach a detectable level of antibodies.
If your test result is reactive, the Red Cross may contact you to request additional information and conduct further testing as part of a research study.
Positive test result: Indicates the detection of specific antibodies to the virus that causes COVID-19. A positive test result indicates that you were likely exposed to the virus, regardless of whether you experienced symptoms or received a COVID19- vaccine.
If your test result is positive, the Red Cross may contact you to request additional information and conduct further testing as part of a research study.
Negative test result: Indicates that you have not developed antibodies to the virus that causes COVID-19, or you may have antibodies that are present at levels below the test’s threshold for detection. It takes one to three weeks after an infection or vaccination to reach a detectable level of antibodies.
Not Available test result: Some tests may not be completed due to processing issues. Donors will need to have a successful donation to receive COVID-19 antibody results. Per standard procedures, only successful donations are sent to our laboratory for testing.
Pending test result: Indicates that the test is still in process. Most donors can expect to receive the results of their antibody test within one to two weeks through our Red Cross Blood Donor app or online donor portal. In some situations, final test results may take longer to appear.