What is the difference between Antigen and Antibody Testing? And when should I test?
An antigen test may be recommended for patients that have active symptoms of COVID-19 or may have been recently exposed to COVID-19. An antibody test may be recommended for a person who was previously exposed or had COVID, if they want to know if the body has developed an antibody for COVID-19.
An antigen test is designed to detect antigens early on. As the duration of illness increases, an antigen sample may decrease. Specimens collected after day 5 of illness may be more likely to be negative compared to a RT-PCR assay.
An antibody test is suggested to detect as early as 2 weeks after symptoms start, peaks at 3 to 4 weeks, and decreases over time.
What are the possible benefits of Antibody Test?
The possible benefits of a COVID-19 Antibody test are that results are quick and may help a patient reveal if the body has made antibodies to COVID-19. The test gives a qualitative or “yes/no” result in about 15 minutes. Antibodies may provide additional protection against COVID-19. In addition you may qualify to donate Convalescent donor plasma which may help patients with active COVID-19 infections.
Are the Antigen or Antibody Test FDA approved?
These tests have an Emergency Authorization Use (EUA) from the FDA. FDA may issue EUA when certain criteria are met, which includes that there are no adequate, approved, or available alternatives, and based on the totality of scientific evidence available. An EUA has not undergone the same type of review as an FDA-approved Test and is not FDA-approved or cleared.
What happens if I test positive for COVID-19 testing?
If you test positive for an antibody test, you should continue to follow CDC guidelines including physical distancing, hand-washing, and mask-wearing. A positive test does NOT mean the patient is immune or protected from getting infected again.
What may cause a false negative result?
False negative results may occur in patients who are currently taking, or have a history of taking high doses of biotin (more than 10 mg per day).
What are the possible benefits of Antigen Test?
The potential benefits of a COVID-19 antigen test are relatively quick results. An antigen test may also help your doctor make informed recommendations about your care. In addition, the results may help limit the spread of COVID-19 to your family, friends, and community.
What is the name of the Antigen Test that is being offered?
The antigen test that we are offering is the CareStart Rapid Antigen Test. This test is a lateral flow immunochromatographic assay that provides a qualitative detection of COVID-19 protein antigens.
What is the name of the Antibody Test that is being offered?
The antibody test being offered is called the FaStep Rapid test. This test is a lateral flow immunochromatographic assay that provides a qualitative detection of COVID-19 Antibodies (IgM and IgG). The test is labeled as 100% sensitive and 98.8% specificity. Published data suggests that this test has 100% sensitivity and 80% specificity.
What to expect when arriving for COVID testing
We ask that you call ahead to schedule an appointment (same day appointments are available).
If you are taking the antigen test, when you arrive please park in the curbside pick-up spot and call us at 619-383-6788. The pharmacist will come to your car and administer the test.
The antibody will be administered in the pharmacy with safety precautions.
For the antigen test, the pharmacist will insert a cotton swab into one nostril. The swab is then slowly rotated in a circle three to 5 times.
For the antibody test, the pharmacist will draw a small amount of blood by performing a finger stick prick.
Results will be read in about 10 to 15 minutes.
What does it mean if I test negative for COVID-19 Antigen or Antibody testing?
A negative test does not mean the patient does not have COVID-19 or antibodies. It is best to discuss this with your provider.
If an antigen test was performed, you may want to follow up with a PCR test (results are usually given within 1-2 days to up to 1 week) to confirm, if COVID-19 is still suspected based on exposure history together with other clinical findings.
If you received a negative test with an antibody test, you may have tested too early, or time may lapsed where your body may no longer have antibodies.