2026 ICD-10-CM Diagnosis Code M65.312Trigger thumb, left thumb

ICD-10-CM Codes›M00–M99›M65-M67›M65

ICD-10-CM M65.312
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M65.312 is a billable ICD-10-CM diagnosis code for trigger thumb, left thumb. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 557 through 558. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M65.312
Billable Status
Yes — Valid for Submission
Code Describes
Trigger thumb, left thumb
Short Description
Trigger thumb, left thumb
Same as the full description in the CMS dataset.
Parent Code
M65.31
Trigger thumb

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM65Synovitis and tenosynovitis
This CodeM65.312Trigger thumb, left thumb

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral pediatric trigger thumbs
  • Bilateral trigger thumbs
  • Pediatric trigger thumb
  • Pediatric trigger thumb of left hand
  • Pediatric trigger thumb of right hand
  • Snapping thumb syndrome
  • Thumb joint locking
  • Trigger thumb of left hand
  • Trigger thumb of right hand

Clinical ClassificationClinical

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

CCSR MUS009
Tendon and synovial disorders
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 M65.312 to ICD-9-CMHistory

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

ICD-9-CM
727.03 Trigger 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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M65.312Overview

Is M65.312 (Trigger thumb) a billable code?

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

What MS-DRG does M65.312 group to?

When trigger thumb, left thumb is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8932 to 1.4869 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M65.312?

Under the General Equivalence Mappings, trigger thumb, left thumb converts to ICD-9-CM 727.03 (trigger finger). 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.