Simple blood test sets up care insight for provider clinicians – new concussion diagnosis method uncovered

A routine blood test is set to help doctors diagnose concussion in older Australians more accurately and quickly, according to new research from Monash University and The Alfred. The new option is likely to alter the way head injuries are identified in one of Australia’s most vulnerable populations.

For decades, diagnosing concussion has relied heavily on a patient’s ability to describe what happened and explain their symptoms. For older adults, that process is often far from straightforward, hampering effective and efficient care responses by clinical staff across health and aged care settings.

Memory problems, fatigue, confusion and difficulty concentrating are all recognised signs of concussion. However, they are also common features of ageing, making it difficult for clinicians to distinguish between a mild traumatic brain injury and reference-range age-related changes.

Reliance upon this uncertain approach may be at an end. Researchers have identified a blood-based biomarker that could provide the objective evidence physicians have long been seeking.

A growing public health challenge

Concussion, also known as mild traumatic brain injury (mTBI), is a major and growing health issue worldwide. Older adults experience the highest rates of traumatic brain injury-related hospitalisations and deaths, with falls representing the leading cause of head injuries in this age group. 

For leaders and front-line staff of providers across the country, this is an acute challenge that is faced, in finding strategies to mitigate falls, and respond effectively. 

Unlike younger patients in other care settings, seniors, and by extension stretched front-line staff, often face a more complicated recovery after concussion. They are more likely to experience prolonged symptoms, slower rehabilitation and poorer health outcomes. This has the potential to impact care needs, provider resources, staff skill levels and more.

Exacerbating the sincere desire to provide excellence in care, diagnosis can be difficult in the first place.

A resident may not remember the incident clearly. Some may have lost consciousness. Others may present with symptoms that overlap with conditions such as dementia, stroke, delirium or the side effects of multiple medications. For clinicians and staff on hand, this possesses a significant challenge in the pursuit of care excellence.

“The diagnostic process is often ambiguous,” said lead researcher Dr Gershon Spitz from Monash University’s School of Psychological Sciences.

“Doctors frequently rely on information reported by patients themselves, which can be affected by memory loss, confusion and other factors associated with head injury.”

The protein that reveals hidden brain injury

The new study, published in JAMA Network Open, investigated whether proteins released into the bloodstream after a brain injury could help identify concussion in adults aged 60 years and older.

Researchers recruited 89 participants between the ages of 60 and 84. The group included healthy volunteers, patients with clinically diagnosed concussion and a smaller group whose injuries were suspected but difficult to confirm using traditional diagnostic methods.

The standout performer was a protein known as glial fibrillary acidic protein, or GFAP.

GFAP is released by specialised support cells in the brain called astrocytes when they are damaged. Researchers found that people who had experienced concussion had significantly higher levels of GFAP in their blood compared with healthy participants.

Importantly, GFAP demonstrated excellent diagnostic accuracy, correctly distinguishing concussion cases from healthy controls with an adjusted accuracy score of 0.93 on a scale where 1.0 represents perfect discrimination.

The biomarker performed consistently whether blood samples were taken within 24 hours of injury or later within a 72-hour window.

Perhaps most strikingly, GFAP remained highly effective even in patients whose brain scans showed no obvious signs of injury.

Diagnosing the grey zone

One of the study’s most significant findings involved patients who fell into what clinicians describe as the diagnostic “grey zone”.

These individuals had experienced a plausible head injury and reported symptoms consistent with concussion yet lacked the objective clinical signs normally required for a formal diagnosis.

When researchers applied personalised GFAP thresholds adjusted for age and sex, two-thirds of these patients showed biomarker levels consistent with brain injury.

A second biomarker, brain-derived tau (BD-tau), was elevated in almost 90 per cent of these uncertain cases.

The findings suggest blood biomarkers may help clinicians identify concussions that would otherwise go undetected.

Under current clinical practice, many patients with mild head injuries undergo observation and CT scans to rule out serious complications such as bleeding on the brain. However, a normal scan does not necessarily mean the brain has escaped injury.

Professor Biswadev Mitra, an emergency physician at The Alfred and chief investigator on the study, believes the test could fill an important diagnostic gap.

“Patients may still have significant concussive injuries that are not detected through conventional assessment,” he said.

“For older patients at risk of falls, the ability to identify concussion while they are still in the emergency department could help reduce the risk of future falls and improve long-term outcomes.”

Why age matters

A key discovery from the study was that biomarker thresholds cannot be applied universally.

Researchers found that normal GFAP levels increase naturally with age, meaning an 84-year-old requires a much higher diagnostic threshold than a 60-year-old.

The optimal GFAP cutoff nearly doubled across that age range, rising from around 100 picograms per millilitre to more than 200 picograms per millilitre.

Without age-specific thresholds, doctors risk generating false positives in older patients or missing genuine injuries in younger ones.

The study also identified sex-related differences in some biomarkers, highlighting the need for personalised interpretation rather than a one-size-fits-all approach.

From emergency departments to residential aged care

While the test is still in the research phase, the implications extend well beyond hospital emergency departments. For leaders and clinical staff across aged care, from residential settings to home care providers, the new study is vitally worthwhile to be understood by cross-departmental teams.

Senior author Professor Sandy Shultz from Monash University’s School of Translational Medicine said blood-based concussion testing could eventually become a valuable tool for paramedics, aged care providers and regional health services.

“Timing is critical for effective concussion treatment, particularly in older adults who often have other health conditions that complicate diagnosis,” Professor Shultz said.

“A quick and efficient diagnosis is key to supporting healthy ageing and better long-term outcomes.”

The technology builds on earlier biomarker research conducted in younger populations but is the first to demonstrate strong diagnostic performance specifically in older adults.

Looking ahead

The researchers caution that larger studies will be needed before the test becomes part of routine clinical practice. The study was conducted at a single Melbourne trauma centre and involved a relatively small number of participants.

And yet, the results offer compelling evidence that blood biomarkers could become an important addition to concussion assessment across health and aged care spaces.

For a condition that has long depended on subjective symptoms and uncertain recollections, an objective blood test may provide clinicians with something they have lacked for decades: clear biological evidence that a concussion has occurred.

As Australia’s population ages and fall-related injuries continue to rise, this breakthrough has the potential to leverage a profound impact on senior care. For stretched front-line staff across roles, definitive assessment for concussion suspicion leads to streamlined care responses. Across clinical teams, this new method is set to support doctors in identifying hidden brain injuries earlier, and assisting provider staff in best practice care in response. And importantly, giving older Australians an improved chance of recovery.