On February 14th, the U.S. Food and Drug Administration (FDA) approved a blood test that has been proposed to diagnose concussion. Many media outlets quickly reported this announcement as being a breakthrough in concussion diagnosis. The blood test, in actuality, is intended to help determine whether or not there may be bleeding or other structural injury in the brain after a head injury, necessitating further imaging with a CT scan. Bleeding, or other gross structural injuries of the brain, are not considered synonymous with a concussion. It is readily accepted that a CT scan is not necessary to diagnose a concussion and will be normal in the overwhelming majority of patients ultimately diagnosed with a concussion.
Currently, this test has only been approved for use in adults, rendering it unusable to the majority of patients with sport-related concussion injury. While the promise of a blood test to help diagnose concussion is exciting, this test unfortunately does not accomplish that. Clarifying this fact to the general public is important, as further marketing or promotion of the test as one for concussion confuses the general public, and may create inappropriate demands for it. This will almost certainly lead to increased health care costs, promote misdiagnosis, and reduce vigilance in the setting of concussion in patients who have a "negative" test.
This test may have clinical utility for a health care provider evaluating an adult patient who demonstrates signs or symptoms that are concerning for bleeding or other structural injury as to whether or not further imaging is truly necessary. Concussions may present with a variety of symptoms and severity of those symptoms.
Finally, blood tests should never take the place of a thorough clinical examination and patient history. The American Medical Society for Sports Medicine (AMSSM) strongly recommends that patients with a suspected concussion be evaluated by a healthcare provider with experience and expertise in diagnosis and management of concussion. The AMSSM has a network of over 3,600 physicians with training in concussion diagnosis and management.