DAS 28 - Disease Activity Score Calculator for Rheumatoid Arthritis.
DAS28, a modified version of the original DAS, is a quantitative measure of disease activity used to monitor the treatment of rheumatoid arthritis. DAS28, which stands for "disease activity score," is calculated using a formula that includes the number of tender joints and swollen joints (28 joints maximum). DAS28 is not only useful for assessing patients in clinical practice but for clinical trials as well.

You can calculate the DAS28 ESR (default) or DAS28 CRP