The tests, which detect two protein biomarkers, were cleared by the Food and Drug Administration in 2018 for use in determining which patients with mild TBI should undergo CT scans.
High values of these biomarkers, GFAP and UCH-L1, correlate with death and severe injury, the authors state in their study published in The Lancet Neurology.
Blood Test Could Detect Brain Injury Severity
In the study, researchers from TRACK-TBI, a UCSF-led brain injury research initiative, examined the day-of-injury blood tests of 1,696 patients with TBI, using the Abbott i-STAT Alinity, a portable blood analyzer, and the ARCHITECT assays.
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The results of these blood tests were compared at patients’ six-month assessments, using the Glasgow Outcome Scale Extended, which grades outcomes and quantifies levels of disability following TBI. These outcomes range from death (level 1) to complete recovery with the resumption of normal life but minor deficits in some cases (level 8).
Approximately two-thirds of the patients were male, and their average age was 39. They had been evaluated at 18 Level 1 trauma centers for injuries caused primarily by traffic accidents or falls.
At six months following injury, 7% of the patients had died, and 14% had an unfavorable outcome, with level 2 to 4 injuries ranging from vegetative state to severe disability requiring daily support.
The remaining 67% had incomplete recovery ranging from moderate disabilities requiring assistance outside of the home to minor disabling neurological or psychological deficits.
Researchers found that the day-of-injury blood tests had a high probability of predicting death at six months, 87% for GFAP and 89% for UCH-L1; and a high probability of predicting severe disability at the same timepoint, 86% for both GFAP and UCH-L1.
The blood tests may also guide discussions with families in the cases of catastrophic injuries, he said, and assist in mass casualty situations where they may play a critical role in triage and resource allocation.
Blood Test: A Future Tool for Traumatic Brain Injury
Researchers wanted to see if accuracy in predicting outcomes would be boosted if the two blood tests were done together and combined with prognostic models that looked at variables like age, motor score, pupil reactivity, and CT characteristics.
They found that in patients with severe and moderate TBI, the accuracy of predicting death and severe disability increased to 94% and 89%, respectively. But in patients with mild TBI, the probability of predicting complete recovery versus incomplete recovery increased only to 69%.
Therefore, although structural brain injury, as measured by GFAP and UCH-L1, as well as CT scanning, may play a predominant role in determining poor outcomes in moderate and severe TBI, mechanisms of injury relating to poor outcomes after mild TBI are not yet fully understood.
Developing better prognostic tools for TBI patients, which could help predict recovery trajectory and inform therapeutic options.
Source: Medindia
