FDA: Concussion blood test reduces need for CAT scans

The Food and Drug Administration has given the green light to the marketing of the first blood test that could better diagnose concussions in adults.

"We've been looking for decades now for a marker of brain injury that is not simply an assessment of function, as in questioning a person trying to figure out whether there are memory problems or any other functioning issues," said Dr. Raj Narayan, the executive director of the Neuroscience Institute at Northwell Health.

The blood test, called the Banyan brain trauma indicator, will help reduce the need for CAT scans, reducing patients' exposure to radiation, according to the FDA.

"The usual protocol is that you get a CAT scan typically within a couple of hours of the injury," Narayan said. "And then you repeat that CAT scan in about four hours after that."

The test works by measuring two levels of proteins that are released from the brain into your bloodstream within 12 hours of a head trauma, Narayan said.

"It has been very hard to find markers in the blood that correlate with brain injury," he said.

Almost 2,000 people participated in the clinical trial that led to the test's approval. Researchers took blood samples from adults with suspected concussions. They compared those results with cat scan results.

"Let's say a patient comes in with a concussion and the CAT is normal but the blood test shows a significant level of these markers," Narayan said. "Then it gives the physician an extra warning sign that this patient may have suffered a more severe injury than the CAT scan alone would suggest."

The FDA said the brain trauma indicator was able to predict the presence of brain lesions on a CAT scan nearly 98 percent of the time and those who did not have lesions on a CAT scan almost all of the time, indicating that the blood test can reliably predict the absence of brain lesions. This allows doctors to rule out the need for a CAT scan in at least one-third of patients who are suspected of having a concussion.