Age- and Sex-Related Changes of S-100 Protein Concentrations in Cerebrospinal Fluid and Serum in Patients with No Previous History of Neurological Disorder

S-100 is a calcium-binding protein synthesized in astroglial cells in all parts of the central nervous system (CNS). It is present in the body in different subchains, of which the beta form (96%) predominates in the brain (1). S-100 protein is normally not detectable in serum (1), but previous studies have demonstrated that increased S-100 concentrations in cerebrospinal fluid (CSF) are an index of the active phase of cell injury in patients with acute multiple sclerosis exacerbations, intracranial tumors, acute encephalomyelitis, and spinal cord compression (2). High CSF concentrations of the S-100 protein have also been demonstrated in patients with glioblastoma, cervical compression, polyneuropathy, hydrocephalus, subarachnoid hemorrhage, encephalitis, meningitis, and cerebral infarction (3)(4)(5)(6)(7)(8). A previous study demonstrated age-related reference values for S-100 protein in CSF in children and adults with distinct neurological disorders (9).We sampled serum and CSF from 75 men and 35 women undergoing various surgical procedures in spinal anesthesia.The patients had no actual or previous history of neurological disease. The study was performed to establish reference intervals of S-100 protein in CSF and serum.From August 1995 to June 1996, serum and CSF samples were obtained from 110 patients undergoing surgery in spinal anesthesia. Before inclusion in the study, the patients answered a questionnaire concerning known neurological symptoms or diseases, and their hospital records were investigated. The inclusion criteria were as follows: no history of previous neurological symptoms or disease, no previous investigation in a neurological department, no present symptoms indicating any neurological disease, no evidence of malignant disease, …