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ICD-10-CM 2027 diagnosis code

M20.01Mallet finger

Not billable — use a more specific code

M20.01 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M20.01

M20.01 is the ICD-10-CM diagnosis code for mallet finger. It belongs to category M20 (acquired deformities of fingers and toes), block M20-M25 (other joint disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within M20.0 (deformity of finger(s)), M20.01 is specifically for mallet finger. Related codes cover unspecified deformity of finger(s) (M20.00), Boutonniere deformity (M20.02), Swan-neck deformity (M20.03) and other deformity of finger(s) (M20.09).

To report this condition, pick the subcode that matches the documentation: M20.011 (of right finger(s)), M20.012 (of left finger(s)) and M20.019 (of unspecified finger(s)).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under M20.01

Notes that apply from higher levels

Instructions written at a parent level also apply to M20.01.

› From M20.0 Deformity of finger(s)
Excludes1
  • clubbing of fingers (R68.3)
  • palmar fascial fibromatosis [Dupuytren] (M72.0)
  • trigger finger (M65.3)
› From M20 Acquired deformities of fingers and toes
Excludes1
  • acquired absence of fingers and toes (Z89.-)
  • congenital absence of fingers and toes (Q71.3-, Q72.3-)
  • congenital deformities and malformations of fingers and toes (Q66.-, Q68-Q70, Q74.-)

Broader instructions also apply from M20-M25 Other joint disorders and Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to M20.01.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M20.01

Is M20.01 billable?

No. M20.01 is a header code. Report one of its more specific subcodes instead.