Effect of blood alcohol on the diagnostic accuracy of glial fibrillary acidic protein and ubiquitin carboxy-terminal hydrolase L1 for traumatic intracranial hemorrhage: A TRACK-TBI study.

BACKGROUND

Acute intoxication is common in patients evaluated for traumatic brain injury (TBI). However, the effect of elevated blood alcohol levels (BALs) on the diagnostic accuracy of FDA-cleared biomarkers for evaluating traumatic intracranial injury on computed tomography (CT) scan, namely, glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), has not been well studied.

METHODS

We investigated the effect of significantly elevated (>300 mg/dL) and modestly elevated BAL (81-300 mg/dL) at emergency department presentation on the diagnostic accuracy of GFAP and UCH-L1 for predicting a positive CT in patients presenting to 18 U.S. Level I trauma centers within 24 h of TBI as part of the prospective, Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) study. Plasma GFAP and UCH-L1 were measured using Abbott i-STAT Alinity and ARCHITECT assays. Discrimination was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

Of 2320 TRACK-TBI participants studied, 54 (2.3%), 332 (14.3%), 1209 (52.1%), and 725 (31.3%) had significantly elevated BAL, modestly elevated BAL, nonelevated BAL (0-80 mg/dL), and no BAL available, respectively; 48.3% of the cohort had a positive brain CT. Those with significantly elevated and modestly elevated BAL were more likely to have positive CT (61.1% and 60.5% vs. 46.9% and 44.0%) and had higher plasma GFAP and UCH-L1 levels than those with nonelevated BAL and no BAL available. The AUC of GFAP and UCH-L1 combined for predicting CT positivity was higher in those with significantly elevated BAL (0.949) than those with modestly elevated BAL (0.858), nonelevated BAL (0.849), and no BAL available (0.883).

CONCLUSIONS

Modestly and significantly elevated BAL does not lower the diagnostic accuracy of GFAP and UCH-L1 for predicting traumatic intracranial injury on CT. These biomarkers may be useful in decreasing avoidable brain CT imaging in persons with acute alcohol intoxication.