Abstract: Methods for diagnosing and monitoring arthritic disease with an inflammatory joint component in a mammal are described. The methods comprise (a) obtaining a sample of powdered cartilage or synovial fluid from the mammal, (b) mixing the sample with powdered cartilage, or protein that is detectably labeled, (c) determining the amount of label released from the powdered cartilage or protein, the amount being indicative of the level of protease activity, and (d) comparing the level to a standard, or to the level obtained from a sample taken at another time point, wherein the level is an indication of the presence or progression of the arthritic disease.