2027 ICD-10-CM Diagnosis Code M65.942Unspecified synovitis and tenosynovitis, left hand

ICD-10-CM Codes›M00–M99›M65-M67›M65

ICD-10-CM M65.942
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M65.942 is a billable ICD-10-CM diagnosis code for unspecified synovitis and tenosynovitis, left hand. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 557 through 558. Coders also document this condition as synovitis of joint of bilateral hands. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M65.942
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified synovitis and tenosynovitis, left hand
Short Description
Unspecified synovitis and tenosynovitis, left hand
Same as the full description in the CMS dataset.
Parent Code
M65.94
Unspecified synovitis and tenosynovitis, hand

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM65Synovitis and tenosynovitis
This CodeM65.942Unspecified synovitis and tenosynovitis, left hand

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Synovitis of joint of bilateral hands
  • Synovitis of joint of hand
  • Synovitis of joint of left hand
  • Synovitis of joint of right hand
  • Tenosynovitis of bilateral hands
  • Tenosynovitis of left hand
  • Tenosynovitis of right hand

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M65.942: its own notes plus those printed at M65 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 M65 Synovitis and tenosynovitis applies to 133 codes
  • chronic crepitant synovitis of hand and wrist (M70.0-)
  • current injury - see injury of ligament or tendon by body region
  • soft tissue disorders related to use, overuse and pressure (M70.-)

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 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.

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

Hand Injuries and Disorders

No matter how old you are or what you do for a living, you are always using your hands. When there is something wrong with them, you may not be able to do your regular activities.

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement M65.942 replaces the following previously assigned code(s):

  • M65.9 - Synovitis and tenosynovitis, unspecified
FY 2025AddedAdded to the ICD-10-CM code setEffective October 1, 2024.
FY 2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M65.942Overview

What is the ICD-10 code for unspecified synovitis and tenosynovitis, left hand?

The ICD-10-CM code for unspecified synovitis and tenosynovitis, left hand is M65.942 (sometimes written as M65942). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M65.942 (Unspecified synovitis and tenosynovitis, hand) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified synovitis and tenosynovitis, left hand on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M65.942 group to?

When unspecified synovitis and tenosynovitis, left hand is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8873 to 1.4883 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M65.942 be reported with a code from M70.0?

Not as a rule. The Excludes1 note at M65, which applies to M65.942, lists "chronic crepitant synovitis of hand and wrist (M70.0-)". 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).