Reactive test result: Indicates that one antibody test was reactive for COVID-19 antibodies, while another antibody test was negative or was not able to be completed. For most donors, this indicates that antibodies were produced in response to COVID-19 vaccination and you did not have a COVID-19 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.
Positive test result: Indicates the detection of specific antibodies on two different antibody tests to the virus that causes COVID-19. Alternately, a positive test result may indicate the detection of specific antibodies one test that are produced in response to a COVID-19 infection, but not to the vaccine.. A positive test result indicates that you were likely exposed to the virus, regardless of whether you experienced symptoms or received a COVID-19 vaccine.
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: The Red Cross will not be testing routine blood donations for COVID-19 antibodies following June 25, 2021. Individuals who give after that date will now see a “Not Available” test result in the Red Cross Blood Donor App or through our donor portal at RedCrossBlood.org. However, if you donated on or before June 25, your test result will be updated when the testing is complete—in general it can take up to 14 days to receive your result. While rare, some donations given prior to June 25 may not be able to be tested 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.