Epidemiologist Explained How To Decipher Antibody Tests

Epidemiologist explained how to decipher antibody tests

On his Facebook page, epidemiologist Mikhail Favorov explained why a false positive test result can be confused with a positive one.

Photo: facebook.com/michael.favorov

American epidemiologist, Professor Mikhail Favorov founded and heads the Dia Prep System group of organizations, which implements programs to improve public health in Eastern Europe and Central Asia. On his Facebook page, Favorov wrote that doctors often confuse a false-positive test for antibodies with a positive one on the grounds that IgM immunoglobulin was detected in the patient's blood.

According to the expert, the "antibody" marker is IgG, which indicates that the patient had contact with the virus and went to immunization. But IgM immunoglobulins are a marker of the period of illness. If both markers are found in the blood - IgG, IgM - this means that the patient has been ill, most likely asymptomatic, and that was 1-3 months ago, possibly 6.

“If you only have IgG, then you are already a convalescent (note: recovered) and could have encountered a virus some time ago. This is a good sign, usually at this time IgG are already "matured" and protect you better! But if you have found only IgM, then, as a rule, alas, it means "nothing", they are much more often false positive."

In such cases, Favorov recommends taking the test again in 5-7 days to clarify the result.

Earlier, the Moscow mayor's office announced a program of mass testing for antibodies by enzyme immunoassay (ELISA). Testing became available to citizens in 30 polyclinics in the capital last week. Subsequently, it is planned to do up to 200 thousand tests per day.

According to the mayor of the city Sergei Sobyanin, weekly up to 70 thousand Muscovites will receive invitations to come to the clinic and take ELISA tests for the disease.