The Food and Drug Administration (FDA) recently fast-tracked approval for a blood test that’s said to help detect concussions, but experts say the test’s capabilities are being overstated.

The Brain Trauma Indicator, made by Banyan Biomarkers, received the green light to go on the market in less than six months. That’s a pretty quick timeline for the FDA, which granted its approval under its new Breakthrough Devices Program.

While some experts were impressed by the quick approval duration, others warned that the test isn’t the breakthrough everyone’s been waiting for.

In short, it can’t detect concussions. And it’s only meant for adults.

“As with many new medical discoveries, the headlines and the hype can outstrip the reality and I think that has happened here,” said Dr. James P. MacDonald, a physician and sports medicine specialist at Nationwide Children’s Hospital in Ohio.

MacDonald told Healthline that the headline of the FDA’s press release was confusing, as were subsequent stories that reported on it.

“This new test does not diagnose concussion. It cannot ‘detect’ concussions,” MacDonald said.

He added that the new device also doesn’t rule out concussions either.

“What it does do is help a doctor determine whether a patient may need computed tomography (CT) scans after a head injury to see if an ‘intracranial lesion’ may be visible,” he said.

Another issue with the test that wasn’t widely reported is that the test wasn’t studied in children — only adults.

That means it can’t be used on the sidelines at high school football games to pinpoint whether or not a player has experienced a concussion.

“This news will be a bigger deal for the pediatric world when the test is FDA-approved for kids,” MacDonald said.

What it does — and doesn’t do

The test measures levels of UCH-L1 and GFAP, which are proteins that go up after an injury that damages nerve fibers, such as a traumatic brain injury (TBI).

Distinguishing those proteins can help identify a small portion of concussion cases that have intracranial bleeds that are also detectable by CT scan.

These are commonly referred to as “complicated TBI” or “moderate TBI,” and they require neurosurgical intervention, noted Robert Siman, PhD, a professor and researcher with the University of Pennsylvania Center for Brain Injury and Repair.

The vast majority of mild TBI cases don’t have intracranial hemorrhages and are head CT negative, he said. About 25 percent of true mild TBI cases go on to have persistent symptoms.

“We still have no way to identify among mild TBI sufferers the subset at risk of developing these long-lasting brain performance problems,” Siman told Healthline.

For the most part, that means the blood test could rule out bleeding in the head, sparing patients from an unneeded CT scan. But a CT scan alone can’t diagnose a concussion — nor can the new blood test, MacDonald said.

CT scan technology does more than give a “yes” or “no” when it comes to detecting concussions, noted David Putrino, PhD, director of rehabilitation innovation for the Mount Sinai Health System in New York.

“They allow physicians to visualize the brain and evaluate the extent of brain injury, which you simply cannot do with a blood test,” he told Healthline.

Putrino added that the blood test is most effective within 12 hours of an injury. Many people don’t seek medical advice during that time frame — another limitation of solely using the blood test for detection.

The big perk

The biggest benefit of the new test may be its ability to save some patients from unnecessary procedures.

“The major benefit of the new test is that it may reduce the number of unnecessary CT scans ordered by physicians, which would spare patients unnecessary exposure to radiation,” MacDonald said. 

Dr. Elizabeth Matzkin, chief of women’s sports medicine at Brigham and Women’s Hospital in Boston, agreed with that assessment.

The test doesn’t help doctors determine the extent of an injury or give insights as to managing it, she noted.

“There is still a lot of unknowns when diagnosing and treating these injuries,” Matzkin told Healthline.

She did call the new test a “step forward.”

Looking ahead

That said, developing a biomarker for concussions is still important.

Such a test would allow doctors to objectively diagnose concussions.

Currently, diagnosing a person with a concussion is more clinical and the process can be subjective because a physician must interpret test results along with symptoms.

“Having an accurate, quick, and broadly applicable test to more objectively diagnose concussion would be a major game changer,” said MacDonald.

If the Banyan Biomarker test can reduce the frequency of CT scans, that would be a positive effect, he added. That’s because CT scans are the biggest contributor of medical radiation exposure among Americans.

Overall, the medical community sees the test as promising — as long as it’s properly classified.

“It is certainly encouraging to see any type of biomarker test approved by the FDA, but this test appears more appropriate for ruling out more significant brain injuries as opposed to identifying concussions,” said Robert C. Lynall, PhD, co-director of the University of Georgia’s Concussion Research Laboratory.

“While there is certainly benefit in those cases where it may be difficult to rule out intracranial lesion, it does not appear this blood test will necessarily help rule concussion in or out,” Lynall told Healthline.