2026 ICD-10-CM Diagnosis Code M79.662Pain in left lower leg

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.662
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M79.662 is a billable ICD-10-CM diagnosis code for pain in left lower leg. 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
M79.662
Billable Status
Yes — Valid for Submission
Code Describes
Pain in left lower leg
Short Description
Pain in left lower leg
Same as the full description in the CMS dataset.
Parent Code
M79.66
Pain in lower leg

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 CodeM79.662Pain in left lower leg

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral calf pain
  • Pain in bilateral lower legs
  • Pain in calf
  • Pain of left calf
  • Pain of left lower leg
  • Pain of right calf
  • Pain of right lower leg

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

Leg Injuries and Disorders

Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).

Read the full article at MedlinePlus

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

Convert M79.662 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 M79.662Overview

Is M79.662 (Pain in lower leg) a billable code?

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

What MS-DRG does M79.662 group to?

When pain in left lower leg 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 M79.662?

Under the General Equivalence Mappings, pain in left lower leg 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.