Is antibody testing for COVID-19 is beneficial?

-By KI News Team | Jan. 5, 2021, 7:44 p.m.


COVID-19 has expanded into a pandemic since January 2020, being able to infect humans at a lightning fast rate.

Many diagnostic tools used to detect the presence of Coronavirus infection, while some identify virus and some identify antibodies produced to fight the virus. Out of which, the most promising and preferred method is Antibody Testing or also commonly known as Serology Test. The antibodies are produced in human body after they have encountered an antigen that might be bacterial or viral pathogen. This helps the human body to generate immunity.

Antibodies and its target:

There are 3 antibodies that may be checked for positive infection:

 

IgM Immunoglobulin M

 

IgG Immunoglobulin G

 

IgA Immunoglobulin A

 

Produced in Human body

First one to be produced.

Produced later within 14 days of infection

Already Produced and present.

Immune Response

Primary

Secondary

Primary

Size

Largest antibody

Smallest

-

Presence

Blood

Serum (primarily)

Serum, Mucosal secretions, sweat glands, saliva, tears, Blood.

Structure

Monomeric at the surface of B lymphocyte and Pentameric if freely floating in the Blood.

Monomeric

Dimeric

Specificity

Not highly Specific

Highly Specific

Not specific

Role

Binding to majority of the antigens and rapid clearance of the antigens from the Blood stream.

Direct neutralization of the antigen. And causing Antigen clearance via the cell mediated process. Responsible for Post-infection Immunity.

Protect mucosal surfaces.

Concentration present in blood

10% of total antibody count.

Most abundant: 80% of total antibody count.

10% - 15% of total antibody count.

 

Time for the Test:

The complete test takes around 2-3 days to give the results.

Benefits:

The primitive benefit of having antibody testing is that the results also disclose some other details like:

  • If the person in testing has previously been infected or not
  • The person has been infected since how many days.
  • Immunity of the individual if compromised.

Method of Testing:

These tests are done by taking out some blood and carrying out tests to find the target antibodies by using Immunological methods, like ELISA, Lateral flow assay Chemiluminescent Immunoassay.

Approval of the tests in India:

Antibody testing is used widely in India & is approved by the FDA, NIH, CDC, and NCI.

Limitations:

The antibody tests are not regarded as completely reliable as there can be errors in the binding of the antibodies while testing. The new error that’s generally found is the neutralizing antibodies. These antibodies of IgG type are responsible for preventing the entry of the pathogen. Presence of this antibodies do not mean that the person has a thriving COVID infection. It takes around 3 days to get the results, while the antigen testing requires 2 days.

Thus, this is an effective test with its pro’s and con’s. The government uses this test in addition to the other testing procedures for better results.

Inputs by Vaibhavi Mullassery