[Beta-2-microglobulin and rheumatoid factor levels in the synovial fluid (author's transl)].

: The object of this study was to determine whether levels of beta-2-microglobulin and of rheumatoid factor measured by an enzyme-immunoassay allowed good discrimination between inflammatory and degenerative arthropathies. A multiparametric study of synovial fluid was performed on 85 specimens from patients with rheumatoid arthritis, chondrocalcinosis, mechanical arthritis and traumatic arthopathies. A beta-2-microglobulin level of less than 4 mg/l is a result very mich in favor of a non-inflammatory arthropathy (48/49 cases). The quantification of intra-articular rheumatoid factor allows for reclassification in the context of sero-negative rheumatoid arthritis.