Abbott (ABT -0.64%) announced Wednesday it is launching a third test for SARS-CoV-2 -- and its first antibody test for the coronavirus.

Antibodies are blood proteins produced by the body in the latter stages of fighting an infection, and which bind to antigens -- molecules on the surface of alien substances, such as bacteria and viruses. Those antibodies can persist in the bloodstream for months or years following a person's recovery from an illness. Abbott's new product tests for the presence of a particular antibody, IgG, that is produced during a SARS-CoV-2 infection.

A coronavirus colony.

Image source: Getty Images.

Abbott's previous two tests were molecular; a positive result indicates that a person currently has the coronavirus. Antibody tests are different, as they can determine whether the patient was previously infected or otherwise exposed.

In addition to determining whether a person has been exposed to or infected by the coronavirus, the new test's results will aid researchers in determining how long it remains in the body, and whether those who have fought it off once develop an immunity from further infection.

The medical device and pharmaceutical company aims not only to roll out the new test quickly -- the first shipments should go out on Thursday -- but also with significant volume. It said its goal is to ship almost 1 million of them this week, and 4 million by the end of the month. Ultimately, it would like to ramp production up to 20 million in June and in future months.

This news helped lift Abbott shares by 1.5% in mid-afternoon trading Wednesday, in contrast to the wider stock market as reflected by the S&P 500, which was down by more than 2%.