M05.A – Abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis

ICD-10-CM 2027 diagnosis code · Inflammatory polyarthropathies

Billable code

ICD-10-CM code M05.A
Code
M05.A (claims format: M05A)
Description
Abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis
Short description
Abn rheu fctr & anti-citrul protein antibody w rheu arthrit
Billable
Yes – valid for HIPAA-covered transactions
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
13. Diseases of the musculoskeletal system and connective tissue (M00-M99)
Block
M05-M14 Inflammatory polyarthropathies
Parent codes
M05

Notes for M05.A

Code first:
  • rheumatoid arthritis with rheumatoid factor by site, if known (M05.00 to M05.8A)

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

M05 – Rheumatoid arthritis with rheumatoid factor

Excludes1 (not coded here):
  • rheumatic fever (I00)
  • juvenile rheumatoid arthritis (M08.-)
  • rheumatoid arthritis of spine (M45.-)

Index terms for M05.A

Entries in the ICD-10-CM alphabetic index that lead to this code:

Related codes in M05

Frequently asked questions

What is ICD-10 code M05.A?

M05.A is the ICD-10-CM code for abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis, in the block M05-M14 (Inflammatory polyarthropathies).

Is M05.A a billable code?

Yes. M05.A is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does M05.A belong to?

It belongs to category M05 – Rheumatoid arthritis with rheumatoid factor.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.