Is M05.9 a billable ICD-10-CM code?

Yes. M05.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does M05.9 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).

What cannot be coded together with M05.9?

M05.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M05.9 (M05) and apply to it just the same.

M05.9

M05.9 — Rheumatoid arthritis with rheumatoid factor, unspecified

Billable / specific codeICD-10-CM

M05.9 is a billable, specific ICD-10-CM code for rheumatoid arthritis with rheumatoid factor, unspecified. It is valid for submission on a claim.

Excludes1 inherited from the categories above M05.9

These are not written on M05.9, but they bind it: a note on a category applies to every code beneath it. Billing M05.9 with anything listed here is a denial.

Written on M05 — Rheumatoid arthritis with rheumatoid factor

rheumatic fever (I00)
juvenile rheumatoid arthritis (M08.-)
rheumatoid arthritis of spine (M45.-)

Other codes that can never be billed with M05.9

These codes carry an Excludes1 note pointing at M05.9. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M05.9 alone.

R76.81Abnormal rheumatoid factor and anti-citrullinated protein antibody without rheumatoid arthritis

Risk adjustment

M05.9 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

M05.9 is named in 24 Medicare coverage policies — 17 listing it as supporting medical necessity, and 7 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
A58883Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A58893Billing 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

How M05.9 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 M05.9.

Arthritis, arthritic›rheumatoid›seropositive

Code history

M05.9 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share M05. If M05.9 is not quite right, the correct code is usually one of these.

Questions about M05.9

Is M05.9 a billable ICD-10-CM code?: Yes. M05.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does M05.9 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).
What cannot be coded together with M05.9?: M05.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M05.9 (M05) and apply to it just the same.