(Reuters) – Abbott Laboratories said on Monday the U.S. Food and Drug Administration has issued an emergency use authorization for its lab-based COVID-19 antibody blood test.

The test, AdviseDx, can be used to identify a type of antibody called Immunoglobulin M (IgM) in blood samples to determine if someone has been exposure to the novel coronavirus, potentially indicating a recent or prior infection.

Abbott has already received emergency use authorization for seven tests, including molecular tests, a rapid antigen test and another test which can detect a type of antibody called IgG.

The FDA’s emergency use authorization allows the use of unapproved medical products in an emergency to diagnose, treat, or prevent serious or life-threatening diseases with no adequate or approved alternatives.

IgG is longer lasting in the body after an infection, but IgM is more useful for determining a recent exposure to the coronavirus as these antibodies become undetectable weeks to months following an infection, Abbott said.

Unlike molecular tests, which can detect whether someone has the coronavirus, antibody tests determine if someone has had a previous infection by detecting disease-fighting proteins called antibodies.

However, antibody tests are not recommended as the sole basis of diagnosis of COVID-19 as these antibodies may not be detected in the early days of the infection.

Shares of Abbott were up 0.5% at $110.21 in early trading.

(Reporting by Manojna Maddipatla in Bengaluru; Editing by Amy Caren Daniel)