Blood test that detects concussions? Don’t believe the hype.

By: Thayne Munce, PhD .

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Headlines buzzed last week with breaking news that the Food and Drug Administration had approved a new blood test for concussions.

This “breakthrough” understandably garnered enormous attention as awareness and concerns about concussions have reached a fever pitch in recent years. Indeed, concussions have arguably become the most important sports medicine topic of our time and have become a centerpiece of many discussions about health and safety in sports.

A concussion is a complex injury that can be challenging to diagnose and difficult to evaluate throughout one’s recovery. A medical diagnosis of a concussion often ends up being a clinical decision that a qualified health care provider makes from assessing a number of subjective signs and symptoms, and, in some cases, a limited number of objective neurologic assessments (balance, reading speed, eye tracking, etc.), though no single diagnostic test for concussion exists.

Thus, access to a simple blood test that could determine if someone has a concussion would have great clinical value. Such a test would help medical staff be more confident when performing sideline evaluations that often occur in a high-pressure environment.

These decisions have a great impact on a player’s health and, in some cases, the outcome of a contest. Most importantly, an objective test would likely ensure that fewer players who suffer a concussion would return to play in an injured state and risk much more severe injury. Conversely, fewer uninjured players would be withheld from play. In a clinic or hospital setting, a blood test for concussion would aid in more timely and accurate diagnoses, and be helpful in ruling out or pointing to a more serious injury.

Misleading

Unfortunately, the FDA’s announcement of the newly approved test was misleading, and several media outlets have further mischaracterized the information presented.

The FDA’s announcement described the new blood test as one that would “aid in the evaluation of concussion in adults.” To the layperson, this description comes across as a test that can diagnose a concussion. In fact, a subsequent New York Time’s headline reflected (and amplified) this foreseeable misinterpretation with the headline “Concussions can be detected with new blood test approved by FDA.”

The problem is that even the intended purpose of the newly approved test is not to detect concussions, but rather to detect the presence of bleeding in the brain, which is a more serious injury.

Brain injuries explained

A concussion is one type of mild traumatic brain injury (mTBI). While all concussions are mTBIs, not all mTBIs are concussions. Most concussions, particularly sport-related concussions, occur without intracranial bleeding. When diagnosing mTBI, clinicians may perform a computed tomography (CT) scan of the brain to inspect for brain bleeds. If found, these injuries require more urgent care, so they are important to rule out if suspected by a clinician.

The new blood test approved by the FDA appears to be accurate at determining if bleeding in the brain exists, potentially saving on health care costs and patients’ exposure to radiation from unnecessary CT scans. However, as Verle Valentine, M.D., primary care physician, Sanford Orthopedics & Sports Medicine and enterprise director of Sanford Health’s clinical concussion program said, “The test does not detect concussions. It may be useful in an emergency department setting, but this test does not confirm a concussion and it certainly does not rule out a concussion.”

Moreover, it takes three to four hours to get results from this test and it has only been approved for use in adults. Consequently, this blood test has little practical value for the majority of sports-related concussion cases. “It won’t change my practice,” Dr. Valentine said. Numerous other sports medicine physicians throughout the U.S. have shared Dr. Valentine’s sentiment since this much-publicized announcement.

Premise is viable

Researchers have been working diligently for many years to develop a simple blood test that can give a quick and accurate “yes or no” diagnosis of a concussion, and the premise remains viable – but the test approved by the FDA last week is not it.

Many individuals, particularly athletes and parents of young athletes, are very concerned and fearful of concussions. It is unfortunate that hyperbolic headlines, intentional or unintentional, have created more confusion among the public.

For now, an objective diagnosis of concussion remains elusive. Patients should be wary of the hype surrounding simple concussion tests and seek qualified health care providers trained in the diagnosis and management of concussions to receive the best possible care.

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