Serum cleaved tau does not predict postconcussion syndrome after mild traumatic brain injury.

Our objective was to determine if the biomarker for axonal injury, serum cleaved tau (C-tau), predicts postconcussion syndrome (PCS) in adults after mild traumatic brain injury (mTBI). C-tau was measured from blood obtained in the emergency department. Outcome was assessed at 3 months post injury using the Rivermead Postconcussion Symptoms Questionnaire and Acute Medical Outcomes SF-36v2 Health Survey (SF-36). Of 50 patients, there were 15 patients with detectable levels of C-tau, 10 patients with abnormal findings on initial head computed tomography (CT) and 22 patients with PCS. One-third of patients with detectable C-tau and 14.3% of patients without detectable C-tau had abnormal findings on head CT (P = .143). Serum C-tau was not detected more frequently in patients with PCS than those without, neither for all patients (P = .115) nor the subgroup with negative head CT (P = .253). C-tau is a poor predictor of PCS after mTBI regardless of head CT result.