2027 ICD-10-CM Diagnosis Code M79.646Pain in unspecified finger(s)

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.646
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M79.646 is a billable ICD-10-CM diagnosis code for pain in unspecified finger(s). It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 555 through 556. Coders also document this condition as pain in finger. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal pain, not low back pain.

This medical diagnosis code is frequently used in Family Practice, Internal Medicine, and Pediatrics medical specialties to designate conditions such pain in limb.

Code Identity

ICD-10-CM Code
M79.646
Billable Status
Yes — Valid for Submission
Code Describes
Pain in unspecified finger(s)
Short Description
Pain in unspecified finger(s)
Same as the full description in the CMS dataset.
Parent Code
M79.64
Pain in hand and fingers

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM79Other and unspecified soft tissue disorders, not elsewhere classified
This CodeM79.646Pain in unspecified finger(s)

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Pain in finger
  • Pain in thumb
  • Pain of joint of hand
  • Thumb joint painful on movement

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M79.646: its own notes plus those printed at M79.6, M79, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Excludes1

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

From M79 Other and unspecified soft tissue disorders, not elsewhere classified applies to 52 codes
  • psychogenic rheumatism (F45.8)
  • soft tissue pain, psychogenic (F45.41)

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 M79.6 Pain in limb, hand, foot, fingers and toes applies to 31 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 M79.646, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming M79.646: they are not reported together with it, unless the two conditions are unrelated.

  • R52 Pain, unspecified
    limb pain (M79.6-) names M79.6-, which includes this code

Excludes2 5

These codes carry an Excludes2 note naming M79.646: its condition is not part of those codes, and both may be reported when the patient has both.

  • G89 Pain, not elsewhere classified
    limb pain (M79.6-) names M79.6-, which includes this code
  • M25.5 Pain in joint
    pain in hand (M79.64-) names M79.64-, which includes this code
  • M25.5 Pain in joint
    pain in fingers (M79.64-) names M79.64-, which includes this code
  • M25.5 Pain in joint
    pain in limb (M79.6-) names M79.6-, which includes this code
  • R29.89 Other symptoms and signs involving the musculoskeletal system
    pain in limb (M79.6-) names M79.6-, which includes this code

Clinical ClassificationClinical

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

CCSR MUS010
Musculoskeletal pain, not low back pain
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 M79.646 to ICD-9-CMHistory

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

ICD-9-CM
719.44 Joint pain-hand
Approximate The match is approximate rather than exact.
ICD-9-CM
729.5 Pain in limb
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 M79.646Overview

What is the ICD-10 code for pain in unspecified finger(s)?

The ICD-10-CM code for pain in unspecified finger(s) is M79.646 (sometimes written as M79646). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M79.646 (Pain in hand and fingers) a billable code?

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

What MS-DRG does M79.646 group to?

When pain in unspecified finger(s) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8210 to 1.2908 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M79.646 be reported with F45.8?

Not as a rule. The Excludes1 note at M79, which applies to M79.646, lists "psychogenic rheumatism (F45.8)". 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 M79.646?

Under the General Equivalence Mappings, pain in unspecified finger(s) converts to ICD-9-CM 719.44 (joint pain-hand) and 729.5 (pain in limb). The mapping is approximate, so confirm the match fits the documentation.