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Antibody test vs
COVID-19 test in India

What’s the difference?

Antibody test in India - What is it?

An antibody test checks for antibodies, which may tell you whether you had a past infection with the SARS-CoV-2 virus that causes COVID-19. Antibodies are proteins that are produced by your immune system in response to the invading foreign pathogens like bacteria and viruses. An antibody test gives a picture of your current immune status. You can take an antibody blood test across diagnostic centers in India or even get it done at home through online portals such as MFine.

What is the difference between antigen and antibody?

Let’s first start with the meaning of antigen. An antigen is a forfeign substance that triggers your immune system to produce antibodies against it. An antibody, on the other hand, is a Y-shaped protein produced by your body to fight back and neutralize viruses that enter the body. The virus that causes COVID19, which is also referred to as SARS-COV-2, is known to have several antigens. Hence, when you get infected with COVID19, there is a spike in the production of antibodies by your immune system to eliminate the virus. This is the reason why you should take an antibodies test that will show the increased levels of antibodies in blood.

What are the different types of COVID-19 antibody tests in India?

There are two types of COVID-19 antibody tests in India:

IgG Blood Test in India

  • The IgG blood test checks for IgG antibodies which develop in the body 1-3 weeks after COVID-19 symptoms appear
  • Presence of IgG in your blood means that your immune system had encountered coronavirus in the past and has started fighting against it
  • Positive IgG test result shows you have had COVID-19 in the past and you no longer have the disease at present
  • Negative IgG test result shows that IgG antibodies are not present and you did not have COVID-19 infection in the past

Important Note: Based on the IgG test results interpretation, the doctor will advise a suitable course of action. There may be a case wherein you are just recently exposed to coronavirus but get an IgG blood test early, due to which test results will come negative since your body hasn’t had the time to produce the antibodies. This means you could still have COVID-19 infection even though the test result is negative.

IgG IgM Test in India

  • This test checks for IgG and IgM antibodies. IgM will be the first antibody that your body produces after it has encountered the virus that caused COVID-19. IgM disappears soon after the virus is cleared from your body
  • Positive IgG+IgM tests results show that antibodies in the blood in response to the virus have developed and is an indication that you have had an exposure to SARS-CoV-2 virus in the past
  • If you’re symptomatic, you have to go for an RT-PCR test and post-test results appropriate medical action will be taken
  • If you’re asymptomatic, you will be asked to self-quarantine and go for IgG blood test after 7-10 days
  • A Negative IgG IgM test result shows that antibodies have not developed and you have not been exposed to coronavirus in the past
  • If you’re symptomatic, you have to go for an RT-PCR test and post-results, appropriate medical action will be taken
  • If you’re asymptomatic, it means you must continue to take precautions as symptoms may appear later if you have been exposed to coronavirus

Why is it important to get an antibody test in India?

You may have had exposure to the virus that causes COVID-19 in the past without your knowledge since in a majority of cases, people do not show any symptoms to the infection i.e they are asymptomatic. An antibody test in India tells you whether you had been exposed to the virus in the past, and if your body has developed an immune response to it. This data helps our medical experts understand how common the SARS-CoV-2 virus is in India and who might be immune to it.

Antibody test vs COVID-19 test in India - What you need to know

  • Antibody tests are not a replacement for the tests that diagnose COVID-19 infection
  • It does not guarantee that you currently have a COVID-19 infection or have been exposed to the SARS-CoV-2 virus
  • Some positive results may indicate that you have developed antibodies for other illnesses such as a common cold
  • The test does not predict if you will have the required immunity to fight the virus in the future

Note: COVID-19 antibody test should not be used to confirm decisions on returning to work or not practising social distancing.

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Covid RT-PCR

Tests To Diagnose Active COVID-19 Infection

Antigen Test in India (Rapid Diagnostic Test)

  • This test detects specific proteins called antigens that are present only on the SARS-CoV-2 virus
  • It is recommended when someone is showing symptoms of COVID-19 infection
  • The sample is collected via a nasal or throat swab
  • The test is to be taken only when prescribed by a doctor
  • A positive result indicates that you have an active COVID-19 infection
  • A negative result shows antigens have not been detected in the sample
  • Antigen test has low sensitivity which means if you have been tested negative and are still showing symptoms then you need to affirm by going for an RT-PCR test

RT-PCR Test in India(Or Molecular Diagnostic Test)

  • This test detects the genetic material (nucleic acid) of the SARS-CoV-2 virus
  • It is the current gold standard recommendation for someone who is showing symptoms of COVID-19 infection
  • The sample is collected via a nasal or throat swab
  • This test is to be taken only when prescribed by a doctor
  • A positive result indicates that you have an active COVID-19 infection
  • If tested positive, you may be asked to self-quarantine at home or move to isolation at a COVID-19 care centre. If your symptoms are severe, you will be hospitalised.
  • A negative result shows that the virus has not been detected in the sample
  • If tested negative and symptoms still persist, it may also be due to the reason that the viral load may be too low to be detected during the initial stage and hence re-test will be necessary in this case.
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What is the difference between COVID-19 test and antibody test in India?

An antibody test or an antibody screening test in India reveals whether the person has already been exposed to COVID-19 infection by detecting IgG and IgM antibodies in the blood sample. IgM antibodies develop around 2 weeks after infection, followed by IgG antibodies that peak at 3 weeks. This test does not diagnose current COVID-19 infection.

A COVID-19 test in India reveals whether the person is currently exposed to the COVID-19 infection. There are two types of tests to diagnose an active COVID-19 infection: antigen test and RT-PCR test. The test results are rapid and affordable.

Antibody Tests Antigen Test RT-PCR Test
Also called Serology tests Rapid diagnostic test Molecular diagnostic test
What it shows Immune response status COVID-19 diagnosis COVID-19 diagnosis
What it doesn’t show If you have an active COVID-19 infection If you ever had COVID-19 in the past If you ever had COVID-19 in the past
Who can take it? Asymptomatic persons Asymptomatic & Symptomatic persons Asymptomatic & Symptomatic persons
When to take it? Anytime Anytime Anytime
Follow-up tests Sometimes Sometimes Rarely
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FAQs About COVID-19 Antibody Testing

There is a major difference between antibody and antigen. Antibodies are proteins produced by our immune system to fight against the invading foreign pathogens like bacteria and viruses. Antigens are proteins present on the surfaces of pathogens and are capable of triggering an immune response.

There are 5 types of antibodies:

  • IgG: Develops after an infection, provides long term immunity
  • IgM: First antibody to be produced in response to an antigen
  • IgE: Develops during an allergic reaction
  • IgA: Present in tears, saliva and breast milk
  • IgD: Involved in the early stages of immune response

No, the tests to diagnose a current COVID-19 infection are antigen test and RT-PCR test. Antibody screening tests just give a picture of your immune status.

No, you do not need a doctor’s prescription in India for the antibody test.

A blood sample is required for an antibody test.

Yes. The antibody blood tests can either be doubly positive or doubly negative. There are 2% chances that one will be negative and one will be positive. In this case, it is advised to repeat the test after a month.

If you are symptomatic, it is best that you consult a doctor before going for any test. Antibody tests are generally recommended for those who do not have symptoms and wish to know if they have had a past COVID-19 infection they were not aware of.

Children above 12 years of age can take this test. If your child is below the age of 12 years, it is best you take a pediatrician’s advice before booking the antibody screening test.

No, fasting is not required. You can take the test at any time.

As long as you have high levels of IgG and IgM, you are immune to COVID-19 reinfection. Studies are being conducted to determine how long the antibody levels persist in the body and if there are chances of secondary infection.

Remember, it's important to be careful and not engage in self-medication. This can be dangerous and can have unwanted consequences. Stay safe and act on your doctor’s instructions for a speedy and safe recovery!