2027 ICD-10-CM Diagnosis Code M20.012Mallet finger of left finger(s)

ICD-10-CM Codes›M00–M99›M20-M25›M20

ICD-10-CM M20.012
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M20.012 is a billable ICD-10-CM diagnosis code for mallet finger of left finger(s). It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acquired deformities (excluding foot).

Code Identity

ICD-10-CM Code
M20.012
Billable Status
Yes — Valid for Submission
Code Describes
Mallet finger of left finger(s)
Short Description
Mallet finger of left finger(s)
Same as the full description in the CMS dataset.
Parent Code
M20.01
Mallet finger

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM20Acquired deformities of fingers and toes
This CodeM20.012Mallet finger of left finger(s)

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired mallet finger of bilateral hands
  • Bilateral acquired deformity of finger of hands
  • Bilateral acquired deformity of hands
  • Mallet finger of left hand
  • Mallet finger of right hand
  • Rupture of extensor tendon of finger
  • Rupture of tendon of finger
  • Traumatic rupture of extensor tendon of finger
  • Traumatic tear of tendon of hand
  • Traumatic tear of tendon of left hand
  • Traumatic tear of tendon of right hand

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M20.012: its own notes plus those printed at M20.0, M20, block M00-M25, block M20-M25, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block M00-M25 applies to 2,249 codes
  • Disorders affecting predominantly peripheral (limb) joints

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From M20.0 Deformity of finger(s) applies to 15 codes
  • clubbing of fingers (R68.3)
  • palmar fascial fibromatosis [Dupuytren] (M72.0)
  • trigger finger (M65.3)
From M20 Acquired deformities of fingers and toes applies to 33 codes
  • 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.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block M20-M25 Other joint disorders applies to 719 codes
From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

General instructions on how these codes are used.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M20.012, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming M20.012: its condition is not part of those codes, and both may be reported when the patient has both.

  • M21 Other acquired deformities of limbs
    acquired deformities of fingers or toes (M20.-) names M20.-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS023
Acquired deformities (excluding foot)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Finger Injuries and Disorders

You use your fingers and thumbs to do everything from grasping objects to playing musical instruments to typing. When there is something wrong with them, it can make life difficult. Common problems include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M20.012 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
736.1 Mallet finger
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M20.012Overview

What is the ICD-10 code for mallet finger of left finger(s)?

The ICD-10-CM code for mallet finger of left finger(s) is M20.012 (sometimes written as M20012). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M20.012 (Mallet finger) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report mallet finger of left finger(s) on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M20.012 group to?

When mallet finger of left finger(s) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 566, 565, with relative weights from 0.7374 to 1.4909 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M20.012 be reported with R68.3?

Not as a rule. The Excludes1 note at M20.0, which applies to M20.012, lists "clubbing of fingers (R68.3)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of M20.012?

Under the General Equivalence Mappings, mallet finger of left finger(s) converts to ICD-9-CM 736.1 (mallet finger). The mapping is approximate, so confirm the match fits the documentation.