COVID-19 Antibody Testing


This summer, as a thank you for your dedication to maintaining the blood supply in South Texas, all blood donations will undergo a COVID-19 antibody test, at no cost to donors. Results will be sent to you by mail within 14 days of your donation. 

If you test positive, you may be able to save more lives by donating your plasma, which is being used to treat patients fighting for their lives against this virus. More information at

Blood donations are by appointment only. To make an appointment visit

The antibody test is not a diagnostic test. It is not intended for people who are currently experiencing COVID-19 symptoms, and does not check for the presence of the virus. 

If you are feeling ill, please stay home and contact your doctor. 

COVID-19 Antibody Testing FAQs

What is the COVID-19 antibody test? 

The South Texas Blood & Tissue Center has begun testing all eligible blood donors to detect the IgG antibody to COVID-19. Antibodies are proteins that help the body fight infections and may remain in the body for some time. We are using the Abbott antibody test to detect these IgG antibodies to determine if a person was previously infected with the virus that causes COVID-19. This antibody test is 99.4% accurate. 

NOTE: The antibody test is not FDA approved and is not a diagnostic test. It is not intended for people who currently are experiencing COVID-19 symptoms and does not check for the presence of the virus.  Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43 or 229E. If you are having COVID-19 symptoms or have questions about test results, please contact your doctor. 

Do I need to have an appointment to donate and receive the COVID-19 antibody test? 

Yes, you must have an appointment at a donor room or blood drive to donate at this time. Scheduled appointments help us maintain your safety as well as the safety of our life-saving team members. To make an appointment visit

Will the COVID-19 antibody test tell me if I currently have COVID-19? 

No. The COVID-19 antibody test does not test for the presence of the COVID-19 virus. If you are concerned that you have COVID-19 or you are not feeling well, do not make an appointment to donate and do not come to a donor center. STAY HOME and get well. Once you are 14 days past your last symptom, please contact us to become a COVID convalescent plasma donor. 

What does it mean if I test positive for the COVID-19 antibody? 

Antibody production is the body’s response to an infection. A positive COVID-19 antibody test may result from an infection with SARS-CoV-2 or a related coronavirus. Occasionally, false-positive results may occur. If you are concerned about your test results, please discuss directly with your healthcare provider. 

What does it mean if I have a negative antibody test? 

A negative test result means the antibodies produced by exposure to the coronavirus were not detected in your blood. There is also a very small chance (less than 0.6%) that this test can give a false negative result – in other words, you have been previously infected with SARS-CoV-2 but the test did not detect the antibodies. Negative results do not preclude acute SARS-CoV-2 infection. If acute infection is suspected, direct testing for SARS-CoV-2 is necessary. 

Why are you testing for the COVID-19 antibody? 

We are providing this free test to all our donors to demonstrate our appreciation for their lifesaving blood donation. A number of people asked about STBTC offering a COVID-19 antibody test for blood donors. If you test positive for the COVID-19 antibody, you may be able to donate “convalescent plasma” to treat patients suffering from this very serious illness. 

Why is COVID-19 plasma used to help a coronavirus patient? 

Historically, convalescent plasma has been used to help sick patients recover from serious illnesses. Recent studies demonstrate that convalescent plasma containing COVID-19 antibodies may potentially boost a patient’s immune system and help them recover. 

Do I have to be a blood donor to get the COVID-19 antibody test? 

Yes. This test is available only to those who complete a whole blood, platelet, double red blood cell or plasma donation. 

Do I need to have a successful donation to receive my results? 

Yes. We are offering antibody testing only for completed blood donations that will be used for patient transfusion. The COVID-19 antibody test is performed in addition to all FDA-required testing to ensure patient safety. 

If I test positive for the antibodies, does it mean I am immune to COVID-19? 

No. A positive result indicates you have had previous exposure to the COVID-19 virus and your body has developed antibodies. This is not a diagnostic test. Both the FDA and CDC have said they do not know if antibodies to COVID-19 will provide someone with immunity against a future coronavirus infection. Results from antibody testing should not be used to diagnose or exclude acute SARS-CoV-2 infection. Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E. 

Will I receive my results after I donate? 

Yes! Your results will be mailed to you within 14 days of your donation. Please make sure your contact information is correct, including address, phone number and email. 

Is donating blood safe? 

Yes. Blood centers have established multiple procedures and practices to keep donors safe while giving blood. Those precautions, along with recommendations for staying healthy during the COVID-19 pandemic, are at The coronavirus that causes COVID-19 is respiratory and has not been shown to be spread by transfusion. 

How long will South Texas Blood & Tissue Center be providing the COVID-19 antibody testing? 

At this time, South Texas Blood & Tissue Center will provide COVID-19 antibody testing on all completed blood donations until Aug. 31. 

Can my previous donation(s) be tested for the COVID-19 antibody? 

No. However, you are encouraged to book your next appointment before Aug. 31, and your donation will be tested at that time. To make an appointment visit

Note: This test has not been reviewed by the FDA.