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Blood test may eliminate need for CT scans after TBI

A novel blood test predicted the absence of intracranial injuries on head CT scan after suspected traumatic brain injury with high accuracy, according to findings published in The Lancet Neurology.

“More than 50 million people worldwide sustain a traumatic brain injury (TBI) annually,” Jeffrey J. Bazarian, MD, from the University of Rochester School of Medicine and Dentistry, and colleagues wrote. “Detection of intracranial injuries relies on head CT, which is overused and resource intensive. Blood-based brain biomarkers hold the potential to predict absence of intracranial injury and thus reduce unnecessary head CT scanning.”

Bazarian and colleagues conducted an observational trial to determine if a blood test that detects the combination of ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) can predict traumatic intracranial injuries on head CT scan after TBI.

The researchers studied 1,959 adults aged 18 years or older who visited an ED with suspected, nonpenetrating TBI and a Glasgow Coma Scale (GCS) between 9 and 15. They performed head CT scans and administered the blood test within 12 hours of brain injury then measured UCH-L1 and GFAP in serum. The UCH-L1 and GFAP assay results were compared with head CT results.

Intracranial injuries were detected on CT in 6% of participants. Neurosurgically manageable injuries were seen in less than 1% of participants. Blood tests were positive among 66% of patients and negative among 34% of patients.

The blood test had a sensitivity of 0.976 (95% CI, 0.931-0.995) and a negative predictive value of 0.996 (95% CI, 0.987-0.999). Few participants (< 1%) had a positive CT scan when the biomarker test was negative.

“Based on the results of this multicenter study, routine use of the new biomarker test in EDs could reduce head CT scans by a third in acutely head injured patients thought to be in need of CT scanning, avoiding unnecessary CT-associated costs and radiation exposure, with a very low false-negative rate,” Bazarian said in press release.

“Our results suggest that patients with mild TBI (initial GCS of 14 or 15) who have no other indication for a CT (such as a focal neurologic deficit), and who have a negative test can safely avoid a CT scan,” he continued. “Those patients with a positive test have a 10% chance of an intracranial lesion and most clinicians would get a CT scan of their head to determine if an intracranial injury exists, and define it further. The extent to which these biomarker results can be applied to patients presenting with more severe injury, that is in those with a GCS less than 14, requires further confirmation.” – by Alaina Tedesco

Disclosure: Bazarian reports receiving research funding from Banyan Biomarkers and BrainScope Company. Please see study for all other authors’ relevant financial disclosures.