[The boundary levels of laboratory data in autoimmune diseases]

The clinical significance of rheumatoid factor, antinuclear antibody, anti-thyroid antibody, CH50 and serologic tests for syphilis (STS) in boundary levels were investigated. The boundary levels were tentatively determined as: RF 5-20 U/ml, ANA 20-40X, anti-thyroid antibody 100-400X and CH50 25-30 U/ml. In STS, cases with biological false positive reaction were examined. In ninety percent of patients with positive anti-thyroid antibody, thyroid antibody, thyroid diseases were demonstrated. However, various disorders were involved at the boundary levels of rheumatoid factor, antinuclear antibody, CH50 and serologic tests for syphilis. To assess the boundary levels of these serological data, it seems important to observe serial data and other clinical and laboratory findings.