10/23/2026
Blood levels of two proteins can help doctors decide whether patients with mild traumatic brain injury need a CT scan or brain MRI, Pitt researchers found.
PITTSBURGH – Blood tests measuring two proteins released after a brain injury could help emergency room doctors identify patients with traumatic brain injury who might otherwise be sent home undiagnosed, according to a University of Pittsburgh School of Medicine study. Researchers identified clinical cutoffs for the two proteins that could guide decisions on CT scans and follow-up care.
Key Takeaways
- A Pitt School of Medicine-led research team identified clinical cutoffs for two blood proteins, GFAP and UCH-L1, that may help identify and triage patients with traumatic brain injury.
- The study, published in the Journal of Neurosurgery, draws on data and biospecimens collected by Pitt's Neurotrauma Clinical Trials Center for TRACK-TBI, a federally funded, multi-center, longitudinal study.
- Researchers found that GFAP levels in the blood within 24 hours of injury could distinguish patients with acute brain injury from those with no evidence of pathology on neuroimaging, while UCH-L1 showed less ability to distinguish between groups.
- About 25% of TBI patients have brain lesions that CT scans miss but that a brain MRI can detect.
- A point-of-care, whole-blood version of the GFAP/UCH-L1 test can deliver results in 15 minutes, and researchers are working to incorporate it into daily emergency department practice.
Each year, about 2.8 million people in the U.S. experience a traumatic brain injury, and many face death, long-term disability or other serious health problems.
"There are amazingly poor long-term outcome rates for people with a TBI who get seen in the emergency department," said Shawn Eagle, Ph.D., assistant professor in Pitt's Department of Neurological Surgery and lead author of the study.
Pitt's Neurotrauma Clinical Trials Center collects data and blood samples from TBI patients treated in the emergency department as part of TRACK-TBI, a federally funded, multi-center, longitudinal study. The center, led by David Okonkwo, M.D., Ph.D., professor of neurological surgery at Pitt and director of neurotrauma at UPMC, and Ava Puccio, R.N., Ph.D., associate professor of neurological surgery at Pitt, serves as the study's primary biorepository.
Previous TRACK-TBI findings show that more than 50% of participants with mild brain injury have functional limitations one year after injury. Eagle suspects a major driver of poor long-term outcomes is that patients are not properly identified in the first place.
"Prior to this research, in the absence of a positive CT scan, there was no objective way to identify if you had a brain injury," he added.
CT scans miss brain lesions that brain MRI scans can detect
For a patient with suspected TBI, a CT scan is usually the first test doctors use. CT scans are inexpensive, widely available and quick, but they miss brain lesions in about 25% of patients that a brain MRI would detect.
"We're sending people home with a negative CT scan, but 1 in 4 have an abnormality visible on MRI indicating that they should have specialized follow-up care," said Eagle.
Many patients with normal CT scans still have symptoms. Brain MRI scans give a more detailed look at brain tissue and can catch damage a CT misses. But MRIs are slow, costly and not practical for emergency triage.
Blood test measuring GFAP and UCH-L1 proteins can detect when CT and MRI findings are abnormal
A blood test measuring two proteins released from the brain after injury can help doctors decide whether a patient needs a CT scan. Results are available in 15 minutes, which can rule out unnecessary imaging.
"We were curious about how the test would perform if you flipped it on its head," he said. "What level could you be pretty certain that someone does have a bleed in their head versus certainty that they don't?"
The two proteins—glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1)—rise in the blood right after injury and fall over time. Researchers examined whether the proteins could distinguish patients with mild TBI who had positive CT scans from those with negative CT scans, and whether they could identify patients with a negative CT scan but a positive brain MRI.
Researchers found that within 24 hours of injury, GFAP levels in the blood could separate patients with an acute brain injury from those with no sign of damage on brain imaging. GFAP, released from glial cells, spikes quickly between four and 20 hours after injury then declines slowly over several days. UCH-L1, a protein released from neurons, was less useful for telling the groups apart in this study.
Point-of-care TBI test moves from research biorepository toward the emergency department
A point-of-care version of the test, using whole blood instead of lab-processed samples, is available for clinical use, making it possible to run the test at a patient's bedside rather than sending samples to a lab.
"We're working to incorporate this test into the daily clinical practice in the ED," said Eagle. He said wider use of the test could lead to broader applications, and he is exploring whether blood biomarkers could help predict patients' long-term outcomes after a traumatic brain injury.
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Frequently Asked Questions
Q: What does the traumatic brain injury blood test measure?
A: The test measures GFAP and UCH-L1, two proteins released into the blood after a brain injury. Researchers found that blood levels of these proteins can help identify patients with an acute brain injury.
Q: Does the blood test replace a CT scan for traumatic brain injury?
A: The test is not meant to replace a CT scan, only add to the tools available for TBI evaluations.
Q: How long does the traumatic brain injury blood test take to deliver results?
A: The point-of-care, whole-blood version of the test delivers results in about 15 minutes, allowing it to be used at a patient's bedside in the emergency department.
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Additional Resources
- Clinical cutoffs for plasma biomarkers to identify intracranial pathology in traumatic brain injury patients with Glasgow Coma Scale scores 13 to 15: a TRACK-TBI study | Journal of Neurosurgery
- Blood Test Can Help Clinicians Better Identify Brain Injury Severity in Patients | EurekAlert!
- Traumatic Brain Injury Symptoms and Treatment | UPMC
- Department of Neurological Surgery | University of Pittsburgh School of Medicine
- Neurosurgery | UPMC
- Press contacts: Kaleigh Connors (ConnorsKA3@upmc.edu), Liz Reid (ReidE4@upmc.edu)
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Authors and Funding
Authors: Additional authors can be found in the Journal of Neurosurgery article.
Funding: Funding for this study was provided by the Department of Defense (W81XWH-13-1-0441, W81XWH-14-2-0176, W81XWH-18-2-0042, and W81XWH-15-9-0001), and the National Institute of Neurological Disorders and Stroke (U01NS086090 and U01NS1365885; RC2NS069409).
