2026 ICD-10-CM Diagnosis Code M79.645Pain in left finger(s)

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.645
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M79.645 is a billable ICD-10-CM diagnosis code for pain in left finger(s). It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 555 through 556. 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
M79.645
Billable Status
Yes — Valid for Submission
Code Describes
Pain in left finger(s)
Short Description
Pain in left 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 CodeM79.645Pain in left finger(s)

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral thumb pain
  • Pain in finger
  • Pain in finger of left hand
  • Pain in finger of right hand
  • Pain in fingers of bilateral hands
  • Pain in left thumb
  • Pain in right thumb
  • Pain in thumb
  • Pain of bilateral hands
  • Pain of left hand
  • Pain of right hand

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 M79.645 to ICD-9-CMHistory

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

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M79.645Overview

Is M79.645 (Pain in hand and fingers) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pain in left finger(s) on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M79.645 group to?

When pain in left finger(s) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8306 to 1.3218 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M79.645?

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

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.