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When to Get an Antibody Test and Its Importance
Antibody testing, also known as a serology test, detects the presence of antibodies in your blood. These antibodies are produced by your body in response to diseases like COVID-19 or vaccinations.
The FDA refers to the COVID-19 antibody test as the SARS-CoV-2 antibody test. It determines if you have antibodies to the SARS-CoV-2 virus in your blood, indicating either a past infection or recovery from COVID-19.
The CDC states that the COVID antibody test can also provide insights into how well your immune system defends against the virus and help understand population-level protection.
The primary purpose of antibody testing, according to the CDC, is to determine if you have COVID-19 antibodies from a previous infection. However, it should not substitute viral COVID testing for detecting current infections or assessing immunity post-vaccination.
Diagnostic Tests for COVID-19
To diagnose COVID-19, the CDC recommends viral tests. These tests determine if you are currently infected with SARS-CoV-2.
During a viral test, a healthcare professional collects a sample from your nose or mouth. The sample is then analyzed using either a polymerase chain reaction (PCR) test or an antigen test.
The National Institutes of Health explains that a PCR test identifies the DNA or RNA of a pathogen or abnormal cells in a sample. Most viruses, including COVID-19, contain DNA or RNA.
PCR tests can detect COVID-19 in its early stages, with results typically available within a few days, according to the CDC.
According to the Massachusetts Institute of Technology, an antigen test detects SARS-CoV-2 molecules on the virus’s surface. These rapid tests provide results within minutes and can be performed at home or by a healthcare professional. To find COVID testing locations near you, check out the directory provided by 5 WS.
How Are These Tests Different from Antibody Tests?
Antigen tests differ from antibody tests in that they directly detect the presence of the SARS-CoV-2 virus. On the other hand, antibody tests identify the antibodies produced in response to the virus or other diseases.
Understanding COVID-19 Antibody Test Results
A positive result from a COVID antibody test suggests a previous SARS-CoV-2 or COVID-19 infection.
A negative result, as per the FDA, may indicate that you had a previous SARS-CoV-2 infection, but your body has not yet produced detectable antibodies, or the antibody levels are too low for the test to detect.
Antibody Tests for Other Disorders
Aside from COVID-19, antibody tests can also screen for antibodies related to other diseases, such as measles, mumps, hepatitis, mononucleosis, and varicella-zoster virus.
Your doctor may recommend antibody testing for these diseases to assess your vaccination status, the need for boosters, or to identify autoimmune conditions like lupus. Occasionally, schools or workplaces may require antibody testing, as noted by the National Institutes of Health.