Synovial fluid total hemolytic complement activity in rheumatic diseases - a reappraisal.

The varied and contradictory claims made of the clinical value of measuring total hemolytic complement activity in rheumatic diseases prompted a reappraisal of its role, and a review of the literature, taking into account the anomalies of assay and the semi-quantitative nature of the procedure. We found that measurements of synovial fluid (SF) total hemolytic complement activity were of limited value in determining the diagnosis or prognosis of joint diseases. Also there was no significant relationship between SF total hemolytic complement activity and either clinical activity or other laboratory findings. We believe that measurements of SF complement activity will prove of little use as a guide to the effectiveness of drug therapy.