A66.6 vs M25.4
A66.6 (Bone and joint lesions of yaws) compared with M25.4 (Effusion of joint), 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. M25.4 carries an Excludes1 note covering A66.6: “hydrarthrosis in yaws (A66.6)”
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
| A66.6Bone and joint lesions of yaws | M25.4Effusion of joint | |
|---|---|---|
| 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 | Bone and joint lesions of yaws is a billable ICD-10-CM diagnosis code (A66.6). | Effusion of joint is a non-billable ICD-10-CM category code (M25.4). |
| Includes | bouba frambesia (tropica) pian Yaws ganglion | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources