M20 vs Q66
M20 (Acquired deformities of fingers and toes) compared with Q66 (Congenital deformities of feet), 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. M20 carries an Excludes1 note covering Q66: “congenital deformities and malformations of fingers and toes (Q66.-, Q68-Q70, Q74.-)”
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
| M20Acquired deformities of fingers and toes | Q66Congenital deformities of feet | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) | Q00-Q99 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) |
| Definition | Acquired deformities of fingers and toes is a non-billable ICD-10-CM category code (M20). | Congenital deformities of feet is a non-billable ICD-10-CM category code (Q66). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources