Transforming Traumatic Brain Injury Assessment: The Role of Brain-Specific Biomarkers in Blood

When assessing a traumatic brain injury (TBI), professionals use a variety of techniques, including the Glasgow Coma Scale (GCS), physical exams, subjective questions, and potentially an MRI or CT scan.

First published in 1974, the GCS gave doctors a scale to assess a patient’s injuries based on their responsiveness, including eye-opening, motor, and verbal responses. A patient’s GCS score helps healthcare professionals determine how severe the injury might be and what next steps should look like, including potential imaging, and whether a patient can safely be discharged. Unfortunately, a 2015 study found that GCS scoring accuracy across more than 200 emergency providers was only 33%. Additionally, another study found that an estimated 82% of patients with suspected TBI were given CT scans but more than 90% were negative and showed no evidence of traumatic abnormality.

Biomarkers Change the Game for TBI Assessment

It has been nearly 50 years since the GCS was published, and there is clearly room to innovate and build upon the process of assessing TBI. One way to do this is by providing quick, objective measurements for a potential TBI. That’s where brain injury-specific biomarkers come into play. The biomarkers glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1)appear in the blood after a TBI occurs. Looking for GFAP and UCH-L1 can transform our ability to evaluate TBI. Healthcare professionals have had blood tests for the heart, liver, and kidneys for some time, but they haven’t been able to run blood tests for the brain – until now.

One biomarker, GFAP, reliably indicates whether a patient has a recent mild traumatic brain injury (mTBI). It is a specific marker of glial injury to the brain that can be elevated when brain injury occurs. The levels of this protein are notably unaffected by extracranial trauma or exercise as well, unlike other biomarkers that have been previously studied.

UCH-L1 is a degradation enzyme that is highly specific for neurons. Blood levels can help distinguish between patients who do and do not have a mTBI.

Brain Injury Biomarkers Can Be Detected by FDA-cleared Test

First cleared by the FDA in 2021, and later registered in Europe and other countries, healthcare professionals now have access to a test called the i-STAT TBI Plasma test that can tell them if these two biomarkers’ levels are “Elevated” or “Not Elevated” in a patient presenting with a possible mTBI. This helps them evaluate whether further testing is needed.

This rapid, biomarkers blood test can help healthcare professionals quickly evaluate mild traumatic brain injury, such as concussion – even in cases when a CT scan may be normal. It has a negative predictive value of 99.3% and clinical sensitivity of 95.8%.

What’s Ahead

At least 69 million people are estimated to sustain a TBI each year. Streamlining the TBI assessment process with these biomarkers can potentially decrease unnecessary exposure to radiation while decreasing costs for both healthcare systems and patients — all by answering the broader need to avoid excessive use of CT scans. Patients can also get results quicker when this test is compared to the wait time and the procedure for obtaining a head CT scan. Test results are available on the i-STAT TBI Plasma test in approximately 15 minutes after plasma is placed in the test cartridge.

GFAP and UCH-L1 help rule out the need for a head CT scan and together form an invaluable tool that can revolutionize the way healthcare professionals assess TBI.

In the future, we could see a world where a rapid, portable blood test for concussion is available in urgent care clinics and ambulances, on the sidelines of a game, or even on the playground at school – wherever it’s needed most – to give quick assessments that will lead to the best possible outcomes and care. Pairing an objective diagnostic test that is powered by biomarkers with the assessments used today gives physicians and their patients a clearer picture about what is happening to the brain at a time when it is needed most.

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This article originally appeared in Volume 16, Issue 3 of THE Challenge! published in 2022.