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What are the types of serological tests

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Sarah Martinez

Published Apr 16, 2026

Serology tests look for antibodies in blood. If antibodies are found, that means there has been a previous infection. Antibodies are proteins that can fight off infections.

What is a Serology test?

Serology tests look for antibodies in blood. If antibodies are found, that means there has been a previous infection. Antibodies are proteins that can fight off infections.

What is the difference between the IgM and IgG antibodies tests for COVID-19?

Both SARS-CoV-2 IgM and IgG antibodies may be detected around the same time after infection. However, while IgM is most useful for determining recent infection, it usually becomes undetectable weeks to months following infection; in contrast, IgG is usually detectable for longer periods.

What is the purpose of COVID-19 antibody or serology tests?

SARS-CoV-2 antibody or serology tests look for antibodies in a blood sample to determine if an individual has had a past infection with the virus that causes COVID-19. These types of tests cannot be used to diagnose a current infection.

Which COVID-19 serology tests are approved by the FDA?

The Assure COVID-19 IgG/IgM Rapid Test Device is currently the only FDA authorized COVID-19 POC serology test and is available by prescription only. The FDA continues to work with test developers to expand access to COVID-19 testing.

How long does it take for the body to produce antibodies against COVID-19?

Antibodies can take days or weeks to develop in the body following exposure to a SARS-CoV-2 (COVID-19) infection and it is unknown how long they stay in the blood.

What is a coronavirus disease serology test?

Serology tests look for antibodies in blood. If antibodies are found, that means there has been a previous infection. Antibodies are proteins that can fight off infections.

What is the COVID-19 antibody test?

COVID-19 antibody tests can help identify people who may have been infected with the SARS-CoV-2 virus or have recovered from a COVID-19 infection.

Can the Assure COVID-19 IgG/IgM Rapid Test Device be used to diagnose COVID-19?

The Assure COVID-19 IgG/IgM Rapid Test Device should not be used to diagnose acute SARS-CoV-2 infection.

Can you have COVID-19 and still test negative for antibody test?

A negative test means that you have no COVID-19 antibodies, so you probably were not infected with the COVID-19 virus in the past. Because it takes time for antibodies to develop, false-negative test results can happen if the blood sample is collected too soon after your infection started.

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What are the types of COVID-19 tests?

There are two different types of tests – diagnostic tests and antibody tests.

What is the difference between COVID-19 antibody test and PCR test?

Unlike PCR tests, which commonly use swabs to detect Covid-19, blood samples are usually used for antibody tests. This is because there will be a very small amount of Covid-19 circulating in the blood compared to the respiratory tract, but a significant and measurable antibody presence in the blood following infection.

How much does the Labcorp COVID-19 antibody test cost?

Labcorp will bill the cost of the COVID-19 antibody test directly to your health plan if you are insured, or if you are uninsured, Labcorp will bill the appropriate government program. The cost of the test is $42.13 and is based on rates established by the Centers for Medicare & Medicaid Services (CMS).

Can COVID-19 antibody test detect current infection?

• Antibody tests should generally not be used to diagnose a current infection with the virus that causes COVID-19. An antibody test may not show if you have a current infection because it can take 1 to 3 weeks after the infection for your body to make antibodies.

What causes false negatives in COVID-19 antibody tests?

Having an antibody test too early can lead to false negative results. That’s because it takes a week or two after infection for your immune system to produce antibodies. The reported rate of false negatives is 20%.

What does a negative COVID-19 antigen test result mean in asymptomatic persons?

Negative test results using a viral test (NAAT or antigen) in asymptomatic persons with recent known or suspected exposure suggest no current evidence of infection. These results represent a snapshot of the time around specimen collection and could change if tested again in one or more days.

Does a positive antibody test mean I am immune to the coronavirus disease?

A positive antibody test does not necessarily mean you are immune from SARS-CoV-2 infection, as it is not known whether having antibodies to SARS-CoV-2 will protect you from getting infected again.

What did FDA say about the antigen tests and the Omicron variant of COVID-19?

The agency said early results suggest that antigen tests “do detect the omicron variant but may have reduced sensitivity,” meaning it’s possible the tests could miss an infection, known as a “false negative.”

What is the Sofia SARS antigen FIA COVID-19 test?

The Sofia SARS Antigen FIA is a type of test called an antigen test. Antigen tests are designed to detect proteins from the virus that causes COVID-19, in nasal swabs.

How long does it take to produce antibody after COVID-19 vaccine?

In addition, it takes around two weeks for the body to generate antibodies after COVID-19 vaccination, so even tests to detect the “right” antibody could be negative in the first few weeks after vaccination.

What are antibodies?

Antibodies are proteins made by the immune system to fight infections like viruses and may help to ward off future occurrences by those same infections. Antibodies can take days or weeks to develop in the body following exposure to a SARS-CoV-2 (COVID-19) infection and it is unknown how long they stay in the blood.

Can we use COVID-19 antibody tests to evaluate a person’s level of protection after the vaccine?

Currently authorized SARS-CoV-2 antibody tests have not been evaluated to assess the level of protection provided by an immune response to COVID-19 vaccination.If antibody test results are interpreted incorrectly, there is a potential risk that people may take fewer precautions against SARS-CoV-2 exposure. Taking fewer steps to protect against SARS-CoV-2 can increase their risk of SARS-CoV-2 infection and may result in the increased spread of SARS-CoV-2.

Is the Innova COVID-19 Antigen Rapid Qualitative Test recommended by the U.S. Food and Drug Administration (FDA)?

The U.S. Food and Drug Administration (FDA) is warning the public to stop using the Innova Medical Group SARS-CoV-2 Antigen Rapid Qualitative Test for diagnostic use. The FDA has significant concerns that the performance of the test has not been adequately established, presenting a risk to health.

What are consequences of a false negative COVID-19 test?

Risks to a patient of a false negative test result include: delayed or lack of supportive treatment, lack of monitoring of infected individuals and their household or other close contacts for symptoms resulting in increased risk of spread of COVID-19 within the community, or other unintended adverse events.

How long will I test positive for COVID-19 after having it?

Someone infected with Covid will typically test positive for five to eight days, said Dr. Freedman of the American Society of Tropical Medicine and Hygiene. In rare cases someone might test positive for as long as six weeks, even though the individual is no longer contagious, he said.

What is the COVID-19 PCR diagnostic test?

PCR test: Stands for polymerase chain reaction test. This is a diagnostic test that determines if you are infected by analyzing a sample to see if it contains genetic material from the virus.

Is the PCR test for COVID-19 accurate?

PCR tests remain the gold standard for detecting an active COVID-19 infection. The tests have accurately detected COVID-19 cases since the pandemic began. Highly trained clinical professionals are skilled at correctly interpreting PCR test results and notices like this one from the WHO.

How is the COVID-19 nasal swab test performed?

A fluid sample is collected by inserting a long nasal swab (nasopharyngeal swab) into your nostril and taking fluid from the back of your nose or by using a shorter nasal swab (mid-turbinate swab) to get a sample.