B26.85 vs M01
B26.85 (Mumps arthritis) compared with M01 (Direct infections of joint in infectious and parasitic diseases classified elsewhere), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. M01 carries an Excludes1 note covering B26.85: “mumps arthritis (B26.85)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| B26.85Mumps arthritis | M01Direct infections of joint in infectious and parasitic diseases classified elsewhere | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Mumps arthritis is a billable ICD-10-CM diagnosis code (B26.85). | Direct infections of joint in infectious and parasitic diseases classified elsewhere is a non-billable ICD-10-CM category code (M01). |
| Includes | epidemic parotitis infectious parotitis | — |
| Code first | — | underlying disease, such as: leprosy [Hansen's disease] (A30.-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources