The U.S. Food and Drug Administration (FDA) has approved a new test for emergency use to determine if someone has had COVID-19. The test, called T-Detect, was co-developed by Adaptive Biotechnologies and Microsoft and uses the body’s own T-cells to locate signs that the virus is, or has been, present. This can be extremely helpful for both COVID-19 long-haulers and those who aren’t certain whether or not they’ve been infected.*

What makes T-Detect different from the current antibody test?

The accuracy of the current antibody test has varied, largely due to timing. Antibodies can begin to fade from your bloodstream within two to three months, though in some cases they remain for seven months or longer. It can take several days for antibodies to form after exposure to a virus. If you are tested too quickly, they may not have formed yet. If you are tested too late, they may no longer be able to be detected. 

T-cells, on the other hand, retain unique signals of the virus, similar to the way you retain your response to a significant event in your long-term memory. Scientists don’t know how long the T-cell immune response remains active after a COVID-19 infection, but they are hopeful that the test can help provide diagnoses and treatments for people experiencing symptoms that may be connected to the virus.

“We’re looking for that imprint, like a crime scene investigation,” said Dr. William Li, president of the Angiogenesis Foundation. “So many people had the disease, recovered, never got a clear-cut diagnosis, yet they’re suffering from these bizarre, persisting symptoms. The T-cell test has been really useful in this long tail of COVID to help patients establish where they are.”

What does getting a T-cell test involve?

The T-Detect test is primarily a blood test. After your blood is drawn, T-cell DNA is extracted and sequenced with Microsoft’s artificial intelligence (AI) software. This provides a map of your immune system. “T-cells speak a kind of language,” said Peter Lee, corporate vice president of Microsoft Research & Incubations. “We use machine learning to help translate that into the language of diseases.”

The out-of-pocket cost for those seeking the test is $150, which puts it out of reach for many socioeconomically vulnerable populations. Methods of offsetting that price will be provided to help ensure equitable access and encourage people to get tested.

“This long COVID problem could be a second epidemic to actually emerge from the first,” Li said. “Remarkably, after a year we’re still pining for these proper diagnostic tools, and that’s why this is such an important step forward.”

*Pezenik, S. (2021, Mar. 9). FDA Authorizes New T-Cell Test that Could be Game Changer for COVID-19 Long Haulers. ABC News. https://abcnews.go.com/Health/fda-authorizes-cell-test-game-changer-covid-19/story?id=76318248 

Much about the novel coronavirus, i.e., COVID-19, is still not fully understood. As research progresses and our knowledge of the virus increases, information can change rapidly. We strive to update all of our articles as quickly as possible, but there may occasionally be some lag between scientific developments and our revisions.