Blood tests may soon be used to accurately diagnose concussion and predict long term cognitive disability, heralding a quick and easy way to check for life-threatening damage.

Researchers from the US have discovered that high levels of a particular protein in the blood after traumatic brain injury correlates with brain tissue damage.

The protein biomarker correctly predicted which concussion victims went on to have structural brain damage and persistent cognitive dysfunction following a mild traumatic brain injury (mTBI).

Researchers found that the blood levels of a protein called calpain-cleaved αII-spectrin N-terminal fragment (SNTF) were twice as high in a group of patients following a traumatic injury.

If early indications are proven by larger studies, the blood test could identify concussion patients at increased risk of ongoing neurological complications or further damage and disability if they return to the head-threatening activities.

In the United States alone, more than 1.5 million children and adults suffer concussions each year, with hundreds of thousands of sports-players and military personal enduring mild traumatic brain injuries worldwide.

Current tests cannot determine the extent of the injury or if the injured person will be among the 15 to 30 per cent who experience significant deficits, such as mental processing speed, working memory and the ability to switch or balance multiple thoughts.

“New tests that are fast, simple, and reliable are badly needed to predict who may experience long-term effects from concussions, and as new treatments are developed in the future, to identify who should be eligible for clinical trials or early interventions,” said lead author Dr Robert Siman, a research professor of Neurosurgery.

“Measuring the blood levels of SNTF on the day of a brain injury may help to identify the subset of concussed patients who are at risk of persistent disability.”

The blood tests given on the day of a mild traumatic brain injury showed 100 per cent accuracy in predicting concussions leading to persisting cognitive problems, and an ability to correctly rule out those without functionally harmful concussions in 75 per cent of cases.

The researchers will now determine the robustness of their findings with a second larger study, and determine the best time after concussion to measure SNTF in the blood in order to predict persistent brain dysfunction.

The team also wants to evaluate their blood test for identifying when repetitive concussions begin to cause brain damage and persistent disability.

The recent report has been published in the journal Frontiers in Neurology.