In February 2018, the U.S. Food and Drug Administration (FDA) authorized the marketing of the first blood test to evaluate mild traumatic brain injury (mTBI), commonly referred to as a concussion, in adults. The FDA’s decision was made in less than six months as part of its Breakthrough Devices Program, and it enabled a California-based company to introduce an assay for that purpose. This marks the first-ever approval of a blood test for concussions by the FDA.
The assay works by measuring levels of proteins, known as UCH-L1 and GFAP, that are released from the brain into the blood after a hit to the head. These proteins have been shown to be indicative of brain injuries and other neurodegenerative diseases. For the approval, the FDA evaluated data from a clinical study of 1,947 individual blood samples from adults with a suspected mTBI and reviewed the blood test’s performance in comparison to the results of a computed tomography (CT) scan. Results showed that the assay was able to predict the presence of intracranial lesions on a CT scan 97.5 percent of the time. Further, it was able to predict lack of intracranial lesions on a CT scan 99.6 percent of the time. These findings prove that the test can reliably and accurately indicate whether or not a patient has suffered an mTBI. That rules out the need for a CT scan in at least one-third of patients who are suspected of having mTBI. The FDA thus has validated a less-invasive approach to a concussion diagnosis.
What this means
Patients, patient advocates, researchers, clinicians, and other stakeholders have long advocated for an objective, noninvasive way to detect concussions and improve head health. Currently, most patients with a suspected head injury are examined using a neurological scale, called the 15-point Glasgow Coma Scale. This is typically followed by a CT scan to detect brain tissue damage or intracranial lesions that may require treatment; however, CT scans only show more severe brain bleeding and are not always a good indicator of an mTBI. In fact, the majority of patients evaluated for mTBI do not have detectable intracranial lesions on their CT scans.
Now, hospitals will be able to administer a blood test to detect elevated levels of the proteins indicative of brain injury and, only if there are elevated levels, move forward with a CT scan—thus minimizing the need for unnecessary and expensive scans. This will prevent unnecessary neuroimaging and associated radiation exposure for patients, and it will allow medical professionals to definitively diagnose mTBIs that may have otherwise gone undetected by subjective tests.
Why this matters
The test still lacks the sensitivity needed to diagnose the most minute concussions. Obtaining advanced sensitivity and specificity for a test like this is the only way clinicians will be able to detect brain injuries at their onset, before symptoms present. This is critical for improving safety for athletes in contact sports, for instance, and preventing second-impact syndrome. Research shows that repeated hits to the head can potentially lead to other serious neurodegenerative diseases such as chronic traumatic encephalopathy (CTE) and Alzheimer’s disease later in life.
And it may have implications for society, as well. For one dramatic example: former NFL star Aaron Hernandez, who was convicted of murder and later took his own life while in prison, was diagnosed with CTE post-mortem. We cannot know—we cannot judge whether brain injury was a factor in his crime—but it might never have been committed if an objective test for mTBI had been administered to him after every hit to the head. In the future, professional athletes (and their teams and leagues), armed with information, may be able to make better decisions about how many concussions to sustain before calling it a career.
Where this may lead
The recently approved test alone will have an impact; however, of perhaps greater importance in the long run, the FDA’s approval of a blood test for concussions helps to validate the approach as a viable method. The next step is to advance the technology, making it more sensitive and economical, and work toward a point-of-care device. Bringing a blood test for concussion detection to the sidelines of football and other games could dramatically improve player outcomes.
Now that the assay has been approved, its maker and other vendors are concentrating on increasing the element of sensitivity. Not only will heightened sensitivity enable doctors to diagnose concussions and other brain injuries earlier, but it will also help in the development of improved diagnostics and more effective drugs for TBIs and other neurological diseases. Ongoing research is also focused on improving the speed of the test. With the current test, results take about three to four hours to see. For professional athletes—and for anyone who might have suffered a concussion—that’s too long. Researchers are working on speeding up output time.
Ultimately, a test that can detect proteins in the blood that are indicative of brain injuries or neurodegenerative diseases will be necessary to disrupt today’s insufficient methods. There is reason for optimism that the industry will continue down this path of innovation and discovery. Further advances will also help clinicians gain a better understanding of the long-term effects of concussions and the pathology of diseases associated with repeated head trauma.
