TBI in the blood

ABBOTT PARK, Ill.—The current standard of care for diagnosing traumatic brain injuries (TBI) involves examination, screening questions and a CT scan, but a new option could be available. Abbott shared data this week from its TRACK-TBI (Transforming Research and Clinical Knowledge in Traumatic Brain Injury) study demonstrating that its blood test was capable of detecting mild TBIs even when they were missed by a CT scan.

"Blood-based biomarkers are emerging as an important tool to detect TBI, and this research opens up the next chapter for how the condition is evaluated," said Dr. Geoffrey T. Manley, principal investigator of TRACK-TBI, neurosurgeon and professor of neurosurgery, University of California, San Francisco (UCSF). "Having these sensitive tools could provide physicians more real-time, objective information and improve the accuracy of detecting TBI. This research shows that blood tests have the potential to help physicians triage patients suspected of brain injury quickly and accurately."

In the TRACK-TBI study, 30 percent of patients that presented with a normal CT scan showed signs of TBI when they underwent an MRI. The study consisted of 450 patients who had been admitted to the ER with a suspected TBI. The patients underwent a CT scan, which was read by a radiologist as negative for TBI, then had their blood drawn within 24 hours. They also had an MRI within seven to 18 days post-injury. Nearly 99.1 percent of patients with negative CT scans were classified as having mild TBIs.

The results showed that among the 90 individuals with the highest brain-specific glial fibrillary acidic protein (GFAP) levels, 64 percent were confirmed to have a TBI by the MRI scan. Of the 90 individuals with the lowest GFAP levels, 8 percent were confirmed to have a TBI. Patients with a negative CT scan but a positive MRI presented with higher levels of GFAP than patients with negative CT and MRI scans.

“Our earlier research has shown that even in the best trauma centers, patients with TBI are not getting the care they need,” Manley added. “Now we know that many of these patients with TBI are not even getting a diagnosis.”

Key to the study was Abbott's i-STAT Alinity device, a handheld blood analyzer, and its blood test, which tests the blood for GFAP. When the brain suffers an injury, the damaged cells release proteins that leak into the bloodstream, such as GFAP. This study also monitored for the presence of three other brain proteins in the blood, including S100 calcium-binding protein B, ubiquitin C-terminal hydrolase L1, and neuron-specific enolase protein. Of these four biomarkers, GFAP was found to be the most sensitive determinant of TBI in patients with negative CT scans.

"Healthcare providers rely on blood tests for a variety of conditions because of their accuracy and speed, yet we haven't had a blood test for the brain as part of the standard of care," said Dr. Beth McQuiston, neurologist and medical director, Diagnostics, Abbott. "Abbott's i-STAT device has become a trusted brand in hospitals globally today. In the future, our TBI test and next-generation device could also be added to the standard of care, working together with CT scans and other diagnostic tools to provide doctors with a more complete understanding of a patient's condition."

“These blood-based biomarkers are the next step in the evolution of diagnosing and treating TBI,” Manley agreed. “We are finding that not only are they more sensitive than CT in identifying TBI, but they may be more accurate than the current standard of MRI.”

TBI is a serious health issue with long-term effects. As noted on the TRACK-TBI page on the UCSF website, “In 2013, approximately 2.8 million TBI-related emergency department (ED) visits, hospitalizations and deaths occurred in the United States. TBI is a contributing factor in a third of all injury-related U.S. deaths. An estimated 3.2 to 5.3 million people live with the long-term physical, cognitive and psychological health disabilities of TBI, with annual direct and indirect costs estimated at over $76 billion.”