M13.1
Monoarthritis, not elsewhere classified
Not billable — category only FY2026 2025-10-01 → 2026-09-30
Exclusions 12 never code together
M00-M99chapter
Excludes2
- arthropathic psoriasis (L40.5-)L40.5-
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- compartment syndrome (traumatic) (T79.A-)T79.A-
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 2
Index entries leading here filed at null
No alphabetic index entry points at this code.
Alongside this code 2 same parent — M13
Subordinate codes 8
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 M13.14 Monoarthritis, not elsewhere classified, hand M13.15 Monoarthritis, not elsewhere classified, hip M13.16 Monoarthritis, not elsewhere classified, knee M13.17 Monoarthritis, not elsewhere classified, ankle and foot
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.