© 2022 Verduci Editore s.r.l. All rights reserved.OBJECTIVE: Mild traumatic brain injury (mTBI) cases with a normal CT scanning account for the vast majority of all TBI patients. The aim of this study was to investigate the course of serum Phosphorylated Neurofilament Heavy Chain (pNF-H) levels in the first six hours after trauma in rats in experimental mTBI. MATERIALS AND METHODS: In this experimental animal study, 32 female Sprague-Dawley rats were enrolled equally (n=8) into 3 experimental groups and 1 control group. In experimental groups, animals were exposed to a mTBI with a free fall of 50-gram metal disc from a height of 80 cm. We compared serum pNF-H levels at the 2nd, 4th, and 6th hours after traumatic brain injury in the experimental groups with the control group. RESULTS: Serum pNF-H levels at the 2nd and 4th hours after traumatic brain injury were statistically significantly higher than the control group. Serum pNF-H levels gradually decreased at the 4th and 6th hours compared to the 2nd hour and decreased to a similar level to the control group at the 6th hour after injury. CONCLUSIONS: A high serum pNF-H value, could be used in the diagnosis and management of mTBI patients.