[Biochemical markers in RA]

Inflammatory activity is usually (but not always) accompanied by increases in the plasma concentrations of acute-phase reactants such as C-reactive protein (CRP), fibrinogen etc. The most widely used and most sensitive variable is the CRP value. Increase in the concentrations of acute-phase reactants is accompanied by increase in the ESR (erythrocyte sedimentation rate), though increase in ESR may also be secondary to hypergammaglobulinaemia and anaemia without co-existing inflammation. The measurement of various connective tissue markers in the blood, synovial fluid and urine has opened up the way to new possibilities for evaluating synovial inflammation, pannus formation, and cartilage and bone destruction.