M00.9
Pyogenic arthritis, unspecified
Billable FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 4 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 11 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
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 3
Index entries leading here 4
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) L02.91
- knee — see also Abscess, lower limb
- joint M00.9
- knee — see also Abscess, lower limb
- Infection, infected, infective (opportunistic) B99.9
- Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute) M19.90
- pyogenic or pyemic (any site except spine) M00.9
- Disease, diseased — see also Syndrome
Alongside this code 4 same parent — M00
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.