Background: Diffuse axonal injury (DAI) is an injury that occurs after the onset of traumatic brain injury (TBI), leading to many problems for patients and imposing high costs on the treatment system. Objectives: This study was conducted to investigate the status of laboratory variables in patients with DAI. Methods: This cross-sectional study included 140 patients. Data collection tools were a demographic profile form and magnetic resonance imaging (MRI). Laboratory tests, including glucose, LDL-C, HDL-C, total cholesterol, triglycerides, Hb, HCT, PT, PTT, INR, BUN, creatinine, and CRP were evaluated. Also, specialized devices were used to study the laboratory and radiology variables. Results: Most (61.5%) of the patients were male, 47.1% had a non-governmental occupation, and 55.7% were less than 30 years old. Also, in 87.9% of cases, traffic accidents were the cause of DAI and in 65% of patients, the Glasgow Coma Scale (GCS) was less than 7. In all the laboratory variables differences were observed between the experimental and the control groups. Conclusions: The laboratory variables in patients with DAI had a statistically significant difference compared to the case group, which indicates the negative effect of DAI on laboratory variables. Further studies are required to confirm our results.