Heath Central reports that doctors use ACR20 criteria to gauge how well your rheumatoid arthritis (RA) medications  are working. Vivian P. Bykerk, BSc, MD, FRCPC, rheumatologist at HSS weighs in on this how this criteria is used for RA diagnosis and assessment, and what ACR20/50/70 indicate in clinical trials.

The 20 after ACR stands for 20%, which is essentially what you need to “pass” the ACR20. “If you make an ACR20, you have shown a 20% improvement in three of those five factors,” said Dr. Bykerk. The number also refers to the fact that researchers need to show a 20% improvement in the number of swollen and painful joints of their participants for a medication to be considered valid.

Your rheumatologist is likely to use measures like the Clinical Disease Activity Index (CDAI), which is based on the number of swollen, tender joints that you and your doctor count, explained Dr. Bykerk. The Disease Activity Score DAS-28, generated from this Index, is used both in clinical trials and in doctor’s offices. It’s based on the number of tender and swollen joints you have, results of your ESR blood test (a test that measures inflammation in your body), and your rating of how you feel on a scale from one to 100.

Read the full article at healthcentral.com.