M05.A — Abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis
M05.A is a billable, specific ICD-10-CM code for abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis. It is valid for submission on a claim.
Risk adjustment
M05.A risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 93 Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders0.617 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
M05.A is named in 7 Medicare coverage policies — 2 listing it as supporting medical necessity, and 5 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A58865Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
- A59374Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
- A59434Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
- A59764Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
How M05.A is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to M05.A.
- Abnormal, abnormality, abnormalities›rheumatoid factor and anti-citrullinated protein antibody›with rheumatoid arthritis
Related codes at this level
Codes that share M05. If M05.A is not quite right, the correct code is usually one of these.
- M05.0Felty's syndrome
- M05.1Rheumatoid lung disease with rheumatoid arthritis
- M05.2Rheumatoid vasculitis with rheumatoid arthritis
- M05.3Rheumatoid heart disease with rheumatoid arthritis
- M05.4Rheumatoid myopathy with rheumatoid arthritis
- M05.5Rheumatoid polyneuropathy with rheumatoid arthritis
- M05.6Rheumatoid arthritis with involvement of other organs and systems
- M05.7Rheumatoid arthritis with rheumatoid factor without organ or systems involvement
- M05.8Other rheumatoid arthritis with rheumatoid factor
- M05.9Rheumatoid arthritis with rheumatoid factor, unspecified
Questions about M05.A
- Is M05.A a billable ICD-10-CM code?
- Yes. M05.A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does M05.A sit in the tabular list?
- Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).