Friday, April 1, 2016

Blood Test May Predict Patients With Concussions Days Later

A blood test may be able to detect evidence of a concussion up to a week after the injury occurred, reports a study published in JAMA Neurology. If validated, this simple test could greatly expand the window for diagnosing concussions, especially in patients with mild or moderate traumatic brain injury (TBI).

In recent years, the proteins glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1) have emerged as promising biomarkers for mild TBI. Both proteins are known to become elevated after a head injury and are able to pass the blood-brain barrier.

To understand the behavior of these proteins over days after injury, a team of researchers took repeated blood samples from 584 patients who had been admitted to a trauma center (325 were diagnosed with a mild to moderate traumatic brain injury [MMTBI]; 259 had trauma without MMTBI) over one week. Computed tomography scans of the head were performed in 96.9% patients with MMTBI and in 37.5% trauma patients without MMTBI.

The researchers found that both GFAP and UCH-L1 were detectible within 1 hour of injury. GFAP reached a peak at 20 hours after injury and steadily decreased over 72 hours but was still detectable at 7 days. In contrast, UCH-L1 rose more rapidly after injury than GFAP, reached a peak at 8 hours, and decreased steadily over 48 hours.

When assessing if protein levels could distinguish trauma patients with and without MMTBI, GFAP proved quite predictive, ranging from 80-97% over the various time points (peaking at 97% between the 36-60 hour mark); UCH-L1 was not as accurate, peaking at 77%. GFAP also proved extremely accurate in predicting the patients with MMTBI who required a neurosurgical intervention (seven of the 325 underwent one), with accuracy ranges from 91-100%.

“In the context of developing a point-of-care test, the early and rapid rise of UCH-L1 could be used to detect TBI immediately at the scene of injury in settings such as in the ambulance, on the playing field, or at the battlefield. The longer half-life of GFAP makes it a favorable biomarker to use in both the acute and subacute phases of injury because it is able to detect CT lesions for up to 7 days after injury,” the authors wrote.

For related information, see the Psychiatric News article “Simple Method May Predict Recovery From Concussion.”



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