COVID-19 antibody test or serology test measures protective proteins called antibodies in your blood. During a viral infection, our immune system produces antibodies, or immunoglobulins, as a response to foreign substances called antigens. Covid Antibody tests are often done to check whether a person had COVID-19 in the recent past and have developed antibodies against SARS-CoV-2(Severe acute respiratory syndrome coronavirus 2) infection. The test is also used to confirm whether the person has recovered from SARS-CoV-2 or not.
You can probably get tested for antibodies if:
The COVID antibody test may not be right for you if you are:
The type of covid antibody test and the time of taking the test have an impact on the accuracy of this test. The test won’t detect antibodies if you’re getting tested too early only when the antibodies are developing in your blood. So most likely your healthcare professional won’t recommend this test at least 14 days after the symptoms start.
Another factor that reduces the accuracy of this test significantly is Cross-reactivity. This means there is a chance of cross-reaction between the antibody assays specifically designed for SARS-CoV-2 and related viruses such as SARS-CoV, common coronavirus). This gives false-positive test results.
Based on the availability of tests, the eligibility may differ. A healthcare professional will take your blood sample, typically through a finger prick, or by inserting a needle into a vein in your arm. Your blood sample is tested to detect one or more types of antibodies to the virus, such as:
IgM antibodies- These antibodies occur early in an infection.
IgG antibodies- These antibodies appear later
IgM is the first antibody in the blood upon infection, whereas IgG is the type of antibody found in abundance in our blood.
Antibodies are produced at the end of 7 days or one week after getting infected. After 14 days, IgM reaches its peak. Whereas, IgG antibodies form in a person’s body 14 days after the onset of symptoms. After 8 to 13 days, IgG typically becomes positive and IgG reaches its peak around 21 days.
The major method of this test involves analysing the binding of specific antibodies to targeted antigens, or viral proteins. The most commonly used platforms to conduct COVID antibody tests are:
Within an assay, both the targeted antigens and the blood samples are incubated. If the antibody produced against the virus is found in your blood, then it will bind to the antigen, and thus a positive covid antibody test results will be obtained.
No matter the test results, you don’t need a follow-up, if you don’t have any symptoms. But in case if you have, then you may need to take a diagnostic test to check for signs of active virus.
Since there are chances of getting false-negative results, after getting tested, it’s essential that you follow safety guidelines. Stay home as much as possible, often wash your hands and wear a mask when you’re out.
A person who isn’t experiencing the symptoms of SARS-CoV-2 is an asymptomatic person. The symptoms include fever, cough and body ache. Even if you’re an asymptomatic person, you can take the COVID antibody test, since your body might be fighting off the virus, showing no result. You can confirm the exposure with the virus, by taking a COVID antibody test.
No. The test is not used to diagnose SARS-CoV-2. If you’re experiencing any COVID-19 symptoms, such as fever, cough, muscle pain, shortness of breath, diarrhoea, etc, then you have to talk to your doctor about taking a diagnostic test, such as an RT-PCR that detects the virus.
It’s recommended to take an antibody test if you’re previously tested positive for the virus or don’t have any symptoms even if you had close contact with someone tested positive for the virus. It is also applicable if you had a previous history of COVID-19 like symptoms. But it’s also recommended waiting for two weeks, after the symptoms appear, in order to take an antibody test.
Yes. It’s extremely important that you maintain social distance as well as follow safety guidelines because by having antibodies, it’s not certain that you’re immune to SARS-CoV-2 infection in future. Added to that, even if a person is not infected, he/she can transmit viral particles right from their face, hands and other body parts. This will only increase the chances of infection to the rest.
There is no minimum age limit for taking an antibody test. However, no research has indicated the reduced accuracy for this test in children. The antibody test involves a simple blood draw and sometimes can be challenging for young children since they should remain still during the blood draw and the needle insertion causes mild pain.
There are no specific requirements for an antibody test. The test can be taken with or without Doctor’s prescription as such. There are neither any specific diet recommendations nor a need for 12 hours of mandatory fasting.
You may be able to help COVID-19 affected patients if you have completely recovered from the disease, through donating your plasma. Your plasma now contains the antibodies since your body has fought SARS-CoV-2. Therefore, your plasma can help fight off the disease that patients face.