About the Test
Purpose of the test
The purpose of at-home COVID-19 antibody testing is to check whether you may have had a previous infection with SARS-CoV-2.
Antibody tests can only indicate potential past infection. They cannot be used to determine if you currently have COVID-19. These tests are most often used in specific circumstances:
- Testing people with long-lasting symptoms: Symptoms of COVID-19 can persist for many weeks, and at that point, tests for an active infection may come back negative. In these situations, an antibody test can help determine whether symptoms are likely to be related to a past coronavirus infection.
- Testing people with possible late effects of COVID-19: Certain complications from COVID-19 can develop months after you were initially infected. A positive antibody test can help confirm that you had COVID-19 and may help explain these late-developing effects.
- Health research: Researchers may use antibody tests to estimate how many people have had COVID-19 or to better understand the immune response to COVID-19.
COVID-19 antibody tests cannot be used to prove that you have immunity to COVID-19, and they cannot show whether vaccination was effective.
What does the test measure?
Antibodies are proteins made by the immune system to help defend against pathogens like viruses. The test looks for specific antibodies produced in response to an infection with SARS-CoV-2.
These antibodies are known as immunoglobulins. Types of immunoglobulins include immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG). Each immunoglobulin is produced at a different point after infection, and antibody tests for COVID-19 typically measure IgG because it persists the longest in the blood.
When should I get an at-home COVID-19 antibody test?
Antibody tests for COVID-19 are most commonly used if you have symptoms that could be related to COVID-19 but don’t have an active infection with SARS-CoV-2. This can occur when symptoms persist for several weeks after you were initially infected or when health concerns arise that could be tied to an infection months earlier.
Antibody tests are not recommended if you have signs of a recent infection or have recently tested positive for COVID-19. In addition, you should not use antibody testing to try to determine if you have immune protection against COVID-19 or if you were successfully vaccinated. Antibody test results cannot demonstrate whether you have immunity and are not validated for this purpose.
Currently, at-home COVID-19 antibody tests are authorized when they are recommended by a healthcare professional. You can talk with your physician about antibody testing and your options for taking the test at home.
Benefits and Downsides of At-Home COVID-19 Antibody Test
All of the COVID-19 antibody tests that are currently authorized by the Food and Drug Administration (FDA) involve a blood sample that is analyzed by a laboratory. With at-home testing, the blood sample is taken at home instead of in a doctor’s office or other medical setting.
Home collection of your test sample offers some benefits and downsides. Potential benefits include:
- Convenience: You can take your blood sample on your own time and without having to book an appointment or go to a medical office.
- Simple fingerstick sample: Collecting your blood sample involves only a small prick of the finger, which many people find to be easier and less uncomfortable than a blood draw with a needle.
- Transparent cost: If you have to pay out-of-pocket, the cost is normally clearly displayed and includes all charges including shipping and analysis of your sample.
The potential downsides of at-home COVID-19 antibody tests include:
- Delay in receiving results: Once you take your sample, it has to be mailed to the laboratory where it can be analyzed. As a result, it may take a few extra business days for you to get the results back from your test.
- Requires carefully preparing your test sample: When taking a test at home, there may be a higher risk of contaminating the sample or otherwise preparing it incorrectly. While taking a fingerstick is straightforward, it’s important that you carefully follow all of the provided instructions to reduce the chances of an inconclusive or inaccurate test result.
- Possible out-of-pocket cost: At-home antibody tests may not be covered by your health insurance, and if not, you have to pay the full cost of the test. If you are concerned about cost, check with your insurance provider before getting the at-home test kit.
The Best At-Home COVID-19 Antibody At-Home Tests
Because choices are limited for at-home COVID-19 antibody tests, a practical approach is to go directly to a medical laboratory. Below are our picks for the best at-home and laboratory COVID-19 antibody tests:
Elicity – COVID-19 Antibody Test
Sample: Blood (fingerstick)
Results timeline: Within 3 to 5 business days
The Elicity COVID-19 Antibody Test is our pick for the best overall at-home COVID-19 antibody test. This Elicity product is currently the only FDA-authorized COVID-19 antibody test featuring self-collection of a blood sample.
Detailed test-taking instructions are included in the kit. To obtain your sample, prick your disinfected finger with a very small needle, called a lancet, that is provided in the kit. Then lightly press your finger to a special test paper to apply a drop of blood. Once the blood has dried, place the test paper in the provided biohazard bag and seal it in a prepaid return mailer.
Elicity has partnered with Symbiotica, a medical laboratory that has CLIA certification for meeting established standards for quality control. When your sample arrives at the lab, it is analyzed for the presence of IgG antibodies to SARS-CoV-2.
Test results are typically available 3 to 5 days after the lab receives your sample. You can access your test report by logging into Elicity’s secure online platform.
This at-home antibody test is authorized for patients ages 5 and older, although people under 18 should have the fingerstick administered by an adult.
Labcorp – COVID-19 Antibody Test
Price: $10 service fee, up to $42.13 for testing
Results timeline: Within 1 to 3 business days
Our pick for the most affordable laboratory test is the Labcorp COVID-19 Antibody Test.
With nearly 2,000 patient service centers, Labcorp is one of the nation’s largest medical testing companies. Its CLIA-certified laboratories are frequently used by major health networks and hospitals.
COVID-19 antibody testing can be requested through a patient portal on Labcorp’s website. An independent physician from PWNHealth reviews your request and makes a formal order for the test. You can then visit a nearby Labcorp location to have a routine blood draw.
Results are normally available within 1 to 3 business days after your blood is drawn. You will receive a report that documents whether any antibodies to COVID-19 were found in your blood sample.
Labcorp charges a $10 fee for the physician to order the test. The cost of testing itself can be billed to your health insurance provider or to the federal government. If neither covers your test, you will be invoiced up to $42.13.
Best Prepay Lab Test
QuestDirect – COVID-19 Antibody Test
Results timeline: Within 1 to 2 business days
With the QuestDirect COVID-19 Antibody Test, you prepay a flat rate of $69, plus a $6 physician fee, for testing performed at a local lab.
This antibody test from Quest Diagnostics requires a blood sample that is taken with a standard blood draw. The blood draw usually takes just a few minutes, and the entire process is streamlined by paying online before visiting a Quest patient service center.
With this test, your blood sample is analyzed for IgG antibodies to the spike protein in the SARS-CoV-2 virus. The analysis is typically completed within 1 to 2 business days after you visit the lab.
While Quest Diagnostics offers COVID-19 antibody testing through doctor referrals, the QuestDirect prepayment service allows individuals to order a test directly on the company website.
Though the prepayment option is convenient and straightforward, Quest is not able to bill your insurance company for this testing. You should contact your doctor and insurance provider before scheduling a test if you believe that your health care plan covers COVID-19 antibody testing. The QuestDirect option is only meant for people who do not intend to seek reimbursement through a health insurance plan.
Interpreting At-Home Test Results
The test report will show whether your sample was either positive or negative for antibodies to SARS-CoV-2. A physician should review your test report to help explain its significance in your case.
Normally, if antibodies were found, it indicates that you have previously had COVID-19. However, false positive tests can occur and show antibodies even when you haven’t actually had COVID-19. This can happen if the test incorrectly identifies antibodies to other coronaviruses as antibodies to SARS-CoV-2.
If no antibodies are found, it means that the test does not show indications of a prior SARS-CoV-2 infection, but this does not definitely prove that you have not had COVID-19. Not everyone produces the same amount of antibodies, and antibody levels can decrease over time.
Your doctor can discuss your test results with you and help you understand whether the test is likely to accurately reflect whether you have had COVID-19 in the past.
Are test results accurate?
At-home antibody tests for COVID-19 are generally able to determine whether or not antibodies are present in your blood sample, but no medical test is perfectly accurate. Issues that can affect the accuracy of serology tests for COVID-19 include:
- Testing too early: Antibodies usually aren’t found in the blood until a few weeks after a coronavirus infection. For this reason, testing too soon after infection may return a false negative result.
- Testing too late: While antibodies often last for many months, they may wane to undetectable levels at a faster rate in some people. As a result, testing too long after an infection may lead to a false negative result.
- Cross-reactivity with other antibodies: Other kinds of coronaviruses may cause the body to produce antibodies that the test may incorrectly determine are antibodies to SARS-CoV-2, causing a false positive test result.
- Viral mutations: Genetic variants could change proteins in the COVID-19 virus in a way that impacts antibody testing accuracy, potentially leading to false negative results.
- Prior vaccination: COVID-19 vaccines are designed to cause the body to develop antibodies to the spike protein of SARS-CoV-2, which enables the virus to infect cells. If an antibody test can detect these vaccine-induced antibodies, it may result in a positive serology test even if you have never had COVID-19. If an antibody test is designed to detect antibodies to the nucleocapsid proteins present in a natural COVID-19 infection, then those who are vaccinated but never infected will have a negative serology result.
The dynamic and evolving nature of COVID-19 means that it is important to review these factors with a health professional to understand the accuracy and interpretation of an antibody test for a specific situation.
Do I need follow-up tests?
Whether you need additional testing after a COVID-19 antibody test will depend largely on the test result and the reason why you had the test. Other tests may be needed if you have ongoing health effects related to a prior case of COVID-19. Reviewing your situation with your physician can help identify any relevant tests that may be needed after antibody testing.
Questions for your doctor after at-home testing
Once you have the results of a COVID-19 antibody test, you can talk with your doctor and review some or all of the following questions:
- Does my test result mean that I had COVID-19 before?
- How confident are you in the accuracy of the test result?
- Should I have any additional tests as a follow-up?
At-home antibody tests are only one kind of test related to COVID-19. The following sections discuss how at-home serology tests differ from other types of tests.
How are at-home COVID-19 antibody tests different from antibody tests at a doctor’s office?
The central difference between a COVID-19 antibody test taken at home and one taken at a medical office is how the sample is prepared. In a medical office, a technician or nurse will handle the process of getting blood that can be analyzed. In this setting, a blood sample may be taken from your vein with a needle or obtained with a fingerstick.
For an at-home test, you do the sample collection yourself with a fingerstick that allows you to obtain a drop of blood.
With both types of testing, the sample is then sent to a laboratory where it can be analyzed.
How are at-home antibody tests different from at-home COVID-19 antigen tests?
Antibody tests look for signs of past infection, which makes them different from antigen tests that detect a current infection. Both types of tests have at-home options, but the tests have distinct uses.
Antigens and antibodies are involved in the immune response to SARS-CoV-2. Antigens are proteins on the surface of the SARS-CoV-2 virus that allow the immune system to identify the virus. The number of antigens increases soon after infection and then decreases as the amount of the virus in the body declines. In contrast, antibodies take weeks to form and can last for months. For this reason, an antigen test cannot detect a past infection, and an antibody test cannot diagnose a current one.
The test sample is also different for each of these tests. Antigen tests are conducted on a sample that is taken from the nose, and antibody tests need a blood sample.
How are at-home antibody tests different from at-home COVID-19 PCR tests?
The test sample for a PCR is taken from the nose, throat, or saliva, which makes it different from an antibody test, which is conducted with a sample of blood.