Establishment of a reference interval for β₂-microglobulin in cerebrospinal fluid with use of two commercial assays

Increased concentrations of β₂-microglobulin in cerebrospinal fluid have been used to detect central nervous system involvement with metastatic cancer and with neurological complications of AIDS. However, no adequate reference interval study has been reported for β₂-microglobulin in cerebrospinal fluid. We established a reference interval with both the Abbott IMx microparticle enzyme-linked immunoassay (EIA) (0.6-2.0 mg/L) and the Pharmacia β₂-micro EIA 96 method (0.8-2.2 mg/L) for β₂-microglobulin in cerebrospinal fluid. The two methods correlate well, with the latter method giving slightly higher values. β₂-Microglobulin increases with age in adults by about 0.1 mg/L every 7.5 years, with no significant difference between genders.