A novel blood test may help doctors determine if people who have experienced a blow to the head could have a traumatic brain injury such as bleeding or bruising, according to a study.
The test called Banyan Brain Trauma Indicator, described in The Lancet Neurology journal, aids in the evaluation of patients with a suspected traumatic brain injury or concussion, also known as a mild traumatic brain injury.
Physicians have relied on subjective markers - mainly patient-reported symptoms such as headaches, nausea, or light sensitivity - to make an educated "guess" on which individuals have brain trauma and require a head CT scan, said researchers at the University of Rochester in the US.
Particularly among athletes who may hide symptoms in order to keep playing, a subjective assessment is not always reliable.
The new test provides an objective indicator of injury that can potentially be obtained quickly and easily in busy emergency departments.
In February, the US Food and Drug Administration (FDA) approved the test as part of a fast track programme to get breakthrough technologies to patients more quickly.
The clinical trial included close to 2,000 individuals presenting with a head injury to 22 emergency departments in the US and Europe.
"Many concussion patients don't seek medical care for their injury, a decision due in part to the perception that emergency departments have nothing to offer in terms of diagnosis," said Jeffrey J Bazarian, a professor at the University of Rochester Medical Center.
"The results of this study show that we now have something to offer - a brain biomarker blood test.
"The ability of this test to predict traumatic injuries on head CT scan will soon allow emergency physicians to provide patients with an unbiased report on the status of their brain," said Bazarian.
He believes the tool will be valuable for emergency room physicians and reassuring for concerned patients and families.
The test detects two brain proteins that are present in the blood soon after a hit to the head.
The new study shows that if the test is negative - meaning that the brain proteins are not present - it is highly unlikely that a traumatic intracranial injury exists and that a head CT scan can be safely avoided.
If the test is positive, a brain injury may be present and the patient should receive a head CT scan to further assess the damage and guide treatment.
Approved for use in individuals 18 years and older, the test has the potential to reduce CT scans and the radiation exposure that comes with them.
They are commonly used to evaluate brain injuries, but research shows that less than 10 per cent of head CTs show any injury.
Limiting scans to patients with a positive blood test could eliminate needless radiation; allow people to get in and out of the emergency room faster; and lower health care costs.
The blood test is effective up to 12 hours following injury and picks up the presence of the brain proteins UCH-L1 and GFAP.
Bazarian said these are useful markers because they are not elevated when someone gets hit outside the head, such as the shoulder or abdomen.