This is a single-marker test measuring the concentration of glial fibrillary acidic protein (GFAP) in serum. GFAP is a biomarker of astroglial cell injury and is utilized in the evaluation of neurological conditions, including traumatic brain injury, neurodegenerative diseases, and certain types of brain tumors. Elevated levels of GFAP can indicate astrocyte damage and assist in clinical decision-making for neurological disorders.