Abstract
The C-reactive protein was compared with the erythrocyte sedimentation rate (ESR) and clinical state in 140 cases of streptococcal and allied diseases. In rheumatic fever and rheumatoid arthritis the C-reactive protein determination correlated better with the clinical state than did the ESR. It was inferior to the ESR in evaluating the nephritic state. The test is easy to perform and gives definite positive and negative results. While non-specific, it is valuable in assessing activity in rheumatic fever and rheumatoid arthritis.