OBJECT: In previous studies of traumatic brain injury (TBI), neural biomarkers 
of injury correlate with injury severity and predict neurological outcome. The 
object of this paper was to characterize neurofilament-H (NFL-H) as a predictor 
of injury severity in patients who have suffered mild TBI (mTBI). Thus, the 
authors hypothesized that phosphorylated NFL-H (pNFL-H) levels are higher in 
mTBI patients than in healthy controls and identify which subjects experienced a 
more severe injury such as skull fractures, intracranial hemorrhaging, and/or 
contusions as detected by CT scans.
METHODS: In this prospective clinical study, blood (8 ml) was collected from 
subjects (n = 34) suffering from mTBI (as defined by the American Congress of 
Rehabilitation and Glasgow Coma Scale scores between 13 and 15) at Parkland 
Hospital, Dallas, Texas, on Days 1 and 3 after injury). Additional clinical 
findings from the CT scans were also used to categorize the TBI patients into 
those with and those without clinical findings on the scans (CT+ and CTgroups, 
respectively). The serum levels of pNFL-H were measured using the enzyme-linked 
immunosorbent assay.
RESULTS: Compared with healthy controls, the mTBI patients exhibited a 
significant increase in the serum levels of pNFL-H on Days 1 (p = 0.00001) and 3 
(p = 0.0001) after TBI. An inverse correlation was observed between pNFL-H serum 
levels and Glasgow Coma Scale scores, which was significant. Additionally, using 
receiver operating characteristic curve analysis to compare the mTBI cases with 
controls to determine sensitivity and specificity, an area under the curve of 
100% was achieved for both (p = 0.0001 for both). pNFL-H serum levels were only 
significantly higher on Day 1 in mTBI patients in the CT+ group (p < 0.008) 
compared with the CT- group. The area under the curve (82.5%) for the CT+ group 
versus the CT- group was significant (p = 0.021) with a sensitivity of 87.5% and 
a specificity of 70%, using a cutoff of 1071 pg/ml of pNFL-H in serum.
CONCLUSIONS: This study describes the serum profile of pNFL-H in patients 
suffering from mTBI with and without CT findings on Days 1 and 3 after injury. 
These results suggest that detection of pNFL-H may be useful in determining 
which individuals require CT imaging to assess the severity of their injury.