Antibody Test for Covid-19


Antibody response to infections :

Antibodies are proteins produced by the human body in response to an infection and help fight it off. They can stay in the blood for months to years and help in countering future attacks by the same infection. These antibodies can be produced after vaccination. Vaccination works by evoking these protective antibodies in the body, but without actually giving us an infection.

Detecting and measuring antibodies is important because it can tell you:

• Whether you have any degree of protection against future infections:

Presence of specific antibodies is indicative of protection against future infection by the same strain of virus.

• Whether you have had an infection:

It is common knowledge now that COVID-19 can be completely asymptomatic. So, you may have had an infection without even knowing it.

• Whether the vaccination has worked:

In some cases, especially in people with compromised immune systems, antibody response even post vaccination may not be adequate for protection.

There are 2 main types of antibodies IgM and IgG. As a thumb rule, in most infections, IgM arrives on the scene first (usually within a week to 10 days) and at least a week later, IgG appears. However, this pattern varies from disease to disease. IgM then slowly peters out while IgG persists for years and can provide future immunity against the causative microorganism.

So, usually detection of IgM indicates that the infection is still in its acute phase and detection of IgG indicates the infection has passed.


RT-PCR has been the mainstay in the diagnosis of the disease from the beginning. This is a direct diagnostic test and a positive result is confirmatory of the presence of COVID-19 infection. A positive antibody test, on the other hand, is only a surrogate marker of a recent infection. Therefore, ANTIBODY TEST, BY ITSELF CANNOT BE USED FOR DIAGNOSIS OF AN ACTIVE INFECTION.

When used judiciously and in combination, the results of RT-PCR and antibody tests can be of great help in stratification of the population vis-à-vis actively infected population, recently infected but recovered population, and the normal population.

An algorithm based on these considerations is given below as a general guide for the population at large (source: CDC, Atlanta, USA). . All are encouraged to follow these guidelines and help the healthcare and regulatory authorities in controlling and, if possible, in eradicating the pandemic.

Test Result Interpretation
Viral testing (Testing for current infection – PCR/Antigen) Positive Most likely have an active infection
Negative Most likely do not have an active infection
Antibody testing (Testing for evidence of past infection) Positive Likely had a COVID-19 infection in the past, OR had a successful antibody response after vaccination
Negative Likely never had a COVID-19 infection or never developed antibodies to a past COVID-19 infection
Both Viral Positive, Antibody Positive Most likely have an active infection
Viral Positive, Antibody Negative Most likely have an active infection
Viral Negative, Antibody Positive Likely had and recovered from a COVID-19 infection, OR had a successful antibody response after vaccination
Viral Negative, Antibody Negative Likely never had a COVID-19 infection

Suburban Diagnostics offers the full range of COVID-19 antibody testing.

For the ease of understanding, our antibody tests can be broadly classified into two types:

1. For testing during or after infection

These tests are for detecting antibodies after being diagnosed with COVID-19 infection. As mentioned above, it can tell you whether you have developed antibodies against COVID-19 while giving you protection against future infection.

Test Why?
Anti SARS-CoV-2 Antibody, Total, Serum Most sensitive and earliest marker of immune response after and infection

2. For testing after vaccination

Vaccinations give you protection against COVID-19 by inducing certain specific antibodies. Testing for antibodies post your vaccination can let you know if the vaccination has worked on your immune system. If you have developed the antibodies, a quantitative test can tell you how well your body has responded by measuring the level of antibodies in the blood. This can then be tracked for the future – to assess if the levels have gone up or down.

Test Why?
Anti SARS-CoV-2 Antibody, Post-Vaccination, Quantitative, Serum Test designed to determine development of antibodies and know how much antibodies have developed post vaccination.

Quick reference of Antibody tests at Suburban

Test Code Name of Test Turnaround time MRP(₹)
PATH001489 Antibody Check (SARS-CoV-2-CLIA) 3 hrs. post the same is received at the lab (Cut-off: 7:00 PM) Rs 450/-
PATH001507 Post Vax Antibody Check 3 hrs. post the sample is received at the lab* (Cut-off: 3:00 PM) Rs 1,200/-


  • What is an antibody?

  • Why should a person get a COVID-19 antibody test performed?

  • What does the COVID-19 antibody test do?

  • Can these tests be used to diagnose COVID-19 infection?

  • Does this test correlate with the severity of the disease?

  • How are antibody tests performed?

  • How long does it take to receive test results?

  • If I presently don’t have COVID-19 symptoms, should I get the test?

  • If I have a positive COVID-19 antibody test, am I protected against future infections?

  • When can this test be done?

  • Is social distancing needed if I have antibodies?

  • Should I be concerned for my health on taking the COVID-19 antibody test?

  • Are there special tests for antibodies if I want to check whether my vaccination has been successful?

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