Abbott announced recently that the U.S. Food and Drug Administration (FDA) issued Emergency Use Authorization (EUA) for the company's AdviseDx SARS-CoV-2 IgM (Immunoglobulin M) lab-based serology test for use on the ARCHITECT and Alinity platforms. IgM antibody testing can play an important role in understanding if someone has developed antibodies in response to the virus, indicating a recent or prior infection.

The new IgM antibody test is Abbott's latest test to support in the fight against COVID-19. Since the start of the pandemic, Abbott has received emergency use authorization for seven tests, including molecular tests, a rapid antigen test and an IgG antibody test.

"Abbott has developed tests to detect the virus at each stage of infection so doctors and their patients are equipped with knowledge of how they are responding to the virus and progressing through recovery," said Robert B. Ford, president and chief executive officer, Abbott. "Antibody tests will continue to play an important role to better understand the virus, the prevalence of COVID-19 in an area and where a patient may be in their recovery."

Understanding a person's immune response with antibody tests

While molecular tests detect whether someone has the virus, antibody tests determine if someone had a previous infection by detecting antibodies, such as IgM and IgG.

Abbott first developed an IgG blood test, which often is the antibody that is longer-lasting in the body after infection. This test has been widely adopted and continues to play a key role in understanding if someone has recovered from the virus, as well as contact tracing and epidemiological studies.

The IgM antibody, in comparison, is most useful for determining a recent infection as these antibodies become undetectable weeks to months following infection. Having this more complete picture of where a patient is in their recovery can help healthcare providers determine if treatment, isolation or follow-up visits are needed.

Similar to Abbott's IgG blood test, the IgM test has demonstrated high reliability in both Abbott's research and external virology laboratory studies. Abbott's data demonstrated 99.56% specificity and 95.00% sensitivity for patients tested 15 days after symptom onset.