FDA-approved blood test for TBI may reduce head CTs by a third
A novel blood test given within 12 hours of suspected traumatic brain injury (TBI) may eliminate unnecessary CT scans while sparing patients radiation exposure and reducing costs, a new study in The Lancet Neurology reported—but some experts remain skeptical.
Jeffrey Bazarian, MD, with the University of Rochester School of Medicine in New York, co-led the multicenter study. In it, researchers administered the blood test to patients within 12 hours of suspected TBI. Results showed the method correctly identified 99.6 percent of those who didn't have a traumatic intracranial injury visible on CT imaging.
"Based on the results of this multicenter study, routine use of the new biomarker test in emergency departments 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," said Bazarian and colleagues.
The blood test, which identifies two biomarker proteins released into the bloodstream after a brain injury, was given to 1,959 patients, most with TBI, who presented in the emergency department between Dec. 6, 2012, and March 20, 2014.
Results also showed that 125 participants (6 percent) had intracranial injuries detected on CT and eight (less than 1 percent) had injuries that were neurosurgically manageable. A total of 1,288 (66 percent) patients had a positive glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1) test results, and 671 (34 percent) had negative results. GFAP and UCH-L1 are both proteins that present in the blood quickly after TBI.
The test also achieved a 97.6 percent sensitivity in identifying patients with a TBI on head CT scan.
“The majority of patients presenting with mild traumatic brain injuries like concussion do not have visible traumatic intracranial injuries on CT scans,” said co-lead author Peter Biberthaler, MD, with Technical University of Munich, in Germany, and colleagues. “Given the GFAP and UCH-L1 biomarker test's inherent simplicity, requiring only a blood draw, and its reliability at predicting the absence of intracranial injuries, we are hopeful of its future role in ruling out the need for CT scans in these patients."
Concerns remain
The FDA approved the commercial use of this blood biomarker test, making it the first clinically approved test of its kind in North American, according to the authors.
Still, in a related editorial, Andrew Maas, from Antwerp University Hospital in Belgium, and Hester Lingsma, with the department of public health in the Netherlands, voiced concerns with varying aspects of the test.
“[T]he only clinically relevant question for any new diagnostic test in mild TBI is, Does the test add value (e.g., better outcomes or reduced costs) to currently used biomarkers and decision rules?” they wrote. “Inexplicably, this evaluation was not done and the only explanation given is that the authors did not attempt to improve the test's diagnostic accuracy by adding other clinical variables because they did not feel such a retrospective analysis would meet methodological standards.”
“Our interpretation is that the added value of the test in clinical practice might well be small or even absent, and we strongly encourage the authors to prove us wrong,” the pair concluded. “That would constitute a true addition to science and clinical practice.”
Matt joined Chicago’s TriMed team in 2018 covering all areas of health imaging after two years reporting on the hospital field. He holds a bachelor’s in English from UIC, and enjoys a good cup of coffee and an interesting documentary.