Covid-19: What is ELISA test and how does it work?

Team Udayavani, May 14, 2020, 3:04 PM IST

The ICMR has developed IgG ELISA test called ‘COVID KAVACH ELISA’ for antibody detection for the novel coronavirus.  The test will be used for conducting a national-level surveillance study on the prevalence of Covid-19.

Scientists at NIV Pune were able to isolate the SARS-CoV-2 virus from the samples of those who had been diagnosed with Covid-19, which then led to the development of the test.

The test has high sensitivity and specificity which makes it a better tool for surveillance of infection spread in a community.

The test also has the advantage of being able to evaluate 90 samples together within 2.5 hours, allowing labs to run many samples in a day.

What is ELISA?

ELISA, enzyme-linked immunosorbent assay, is a test that detects and measures antibodies in your blood. This test can be used to determine if you have antibodies related to certain infectious conditions.

How is the test performed?

One needs to sign a consent form before the test. The test involves taking a sample of the blood.

The healthcare provider will first cleanse your arm with an antiseptic.

Next, a tourniquet, or band, will be applied around your arm to create pressure and cause your veins to swell with blood.

A needle will be placed in one of your veins to draw a small sample of blood.

When enough blood has been collected, the needle will be removed, and a small bandage will be placed on your arm where the needle was.

The samples will then be sent to the laboratory. Lab technician will add the sample to a petri dish containing the specific antigen related to the condition for which you are being tested.

If your blood contains antibodies to the antigen, the two will bind together. The technician will check this by adding an enzyme to the petri dish and observing how your blood and the antigen react. If the contents of the dish change color, then you may have the condition.