Alphabetic Index FY2027

M13.1

Monoarthritis, not elsewhere classified

FY2027Chapter 13: Diseases of the musculoskeletal system and connective tissue/M05–M14 Inflammatory polyarthropathies

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

M13.1 is a non-billable ICD-10-CM code header for monoarthritis, not elsewhere classified. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are M13.10 Monoarthritis, not elsewhere classified, unspecified site; M13.11 Monoarthritis, not elsewhere classified, shoulder; M13.12 Monoarthritis, not elsewhere classified, elbow; M13.13 Monoarthritis, not elsewhere classified, wrist and 4 more. Its coding notes include 2 Excludes1 entries and 10 Excludes2 entries.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from M13 Other arthritis

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (10 notes)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

More specific codes under M13.1 8