The identification of circulating autoantibodies contributes to the correct diagnosis as well as to the follow-up of rheumatic diseases. Some autoantibodies are even included in diagnostic and classification criteria for these types of autoimmune diseases. Nowadays there are several relatively specific screening and identification methods for the measurement of autoantibodies available. The type of assay used crucially influences the diagnostic value of the parameters. In generally, routine laboratories should prefer enzyme immune assays (ELISA) using well characterized antigens, although ELISA tests tend to produce more false positive and true weak positive results, which reduce their positive predictive value. Therefore everybody should be aware that the obtained laboratory results can only properly interpreted when there is a correlation with the clinical situation (picture) and when the limitations of the technologies used for autoantibody identification been taken into consideration.

Localization of attacks: affected joints in descending order of frequency (1 = most often; 9 = least often).
Involvement of joints in primary gout  (%):
15-34 %: wrist/fingers;
18-34 %: knee;
6-49: ankle;
8-31 %: toes;
66-76 %: metatarsophalangeal joint of great toe