DRG Instruments, established in 1973, launched an innovative test panel for traumatic brain injury. The test is fully automated for testing blood-based biomarkers of traumatic brain injury, including both glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1). The test is intended for use in adults with a suspected moderate to severe traumatic brain injury. The test has been CE-marked and meets the standards set out by the Clinical Laboratory Standards Institute. Blood samples must be collected from patients within 12 hours or a suspected traumatic brain injury. The test results can be generated within 30 minutes.

This follows the launch of Biomerieux’s VIDAS® TBI (GFAP, UCH-L1) which simultaneously tests glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1). This test obtained CE-marking for European use in 2023.

GFAP and UCH-L1 are blood-based biomarkers that have been shown to be sensitive in distinguishing between individuals with a traumatic brain injury and healthy volunteers (Diaz-Arrastia et al., 2014). The combined use of the two biomarkers has been shown to have greater sensitivity and specificity in detecting a traumatic brain injury (Diaz-Arrastia et al., 2014). As a result, these two biomarkers were approved for use by the Food and Drug Administration in 2018 to help clinicians to determine whether a head CT scan is needed following a suspect traumatic brain injury.

In a recent study including 2,552 patients with a traumatic brain injury, authors found that GFAP and UCH-L1 plasma concentrations had an excellent prognostic value for predicting death and unfavourable outcomes (Korley et al., 2022). Both GFAP and UCH-L1 are elevated within an hour following a brain injury (Papa et al., 2016). However, a more recent study showed that both biomarkers are significantly elevated 30 and 60 minutes following an injury and these biomarkers are associated with the presence of intracranial lesions on an initial CT scan and the need for neurosurgical intervention within 24 hours of injury (Papa et al., 2024). These findings highlight the clinical utility of these biomarkers in supporting clinical decision making and in informing the likely prognosis of a patient following a suspected traumatic brain injury.

GFAP is a protein which is found in astrocytes, a type of glial cell in the central nervous system which supports and protects nerve cells in the brain (Yang and Wang, 2015). Since this protein can be found in biofluids following a traumatic brain injury, it is a helpful biomarker of traumatic brain injury (Yang and Wang, 2015). By contrast, UCH-L1, a protein found in high abundance in neurons is a helpful biomarker for neuronal brain injury (Papa et al., 2016).

Dr McCorry highlights that these tests are some way off entering clinical practice, but a marker that revealed the presence and extent of brain injury would be invaluable in assessing clinical severity.

References

Diaz-Arrastia R, Wang KK, Papa L, Sorani MD, Yue JK, Puccio AM, McMahon PJ, Inoue T, Yuh EL, Lingsma HF, Maas AI, Valadka AB, Okonkwo DO, Manley GT; TRACK-TBI Investigators. (2013). Acute biomarkers of traumatic brain injury: relationship between plasma levels of ubiquitin C-terminal hydrolase-L1 and glial fibrillary acidic protein. J Neurotrauma. 2014 Jan 1;31(1):19-25. 

Korley, F. K., Jain, S., Sun, X. et al., (2022). Prognostic value of day-of-injury plasma GFAP and UCH-L1 concentrations for predicting functional recovery after traumatic brain injury in patients from the US TRACK-TBI cohort: an observational cohort study. The Lancet Neurology, Volume 21, Issue 9, 803 – 813.

Papa  L., Brophy  G.M., Welch  R.D.,  et al. (2016). Time course and diagnostic accuracy of glial and neuronal blood biomarkers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury. JAMA Neurol. 2016;73(5):551-560. 

Papa L, McKinley WI, Valadka AB, et al. (2024). Diagnostic Performance of GFAP, UCH-L1, and MAP-2 Within 30 and 60 Minutes of Traumatic Brain Injury. JAMA Netw Open;7(9):e2431115. 

Yang Z., Wang K.K. (2015). Glial fibrillary acidic protein: from intermediate filament assembly and gliosis to neurobiomarker. Trends Neurosci. 2015 Jun;38(6):364-74.