I just started coding Rheumatology and I have a dilemma. Some of my providers are putting M05.89 (Other rheumatoid arthritis with rheumatoid factor of multiple site) with D89.9 (Disorder involving the immune mechanism) but to me that seems redundant. The patient is sometimes on an immune suppressing medication (such as methotrexate or DMARD or both) and sometimes they are not.

Then I come across claims where they code M06.09 (Rheumatoid arthritis without rheumatoid factor, multiple sites) with D89.9 (Disorder involving the immune mechanism) as above with the patient taking an immune suppressant and sometimes not.

Am I understanding this incorrectly or is this double coding since RA is an immune disease in its own right?

Any help would be greatly appreciated!!!

edited to correct M06.9 to M06.09