2027 ICD-10-CM Diagnosis Code M65.921Unspecified synovitis and tenosynovitis, right upper arm
ICD-10-CM Codes›M00–M99›M65-M67›M65
- Billable — Valid for Submission
- Not Chronic
M65.921 is a billable ICD-10-CM diagnosis code for unspecified synovitis and tenosynovitis, right upper arm. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.
Code Identity
Code Classification
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M65.921: 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.
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.
- 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.
- 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.
Patient EducationClinical
Arm Injuries and Disorders
Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code History & ChangesHistory
Replacement M65.921 replaces the following previously assigned code(s):
- M65.9 - Synovitis and tenosynovitis, unspecified
Questions About M65.921Overview
What is the ICD-10 code for unspecified synovitis and tenosynovitis, right upper arm?
The ICD-10-CM code for unspecified synovitis and tenosynovitis, right upper arm is M65.921 (sometimes written as M65921). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M65.921 (Unspecified synovitis and tenosynovitis, upper arm) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified synovitis and tenosynovitis, right upper arm on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M65.921 group to?
When unspecified synovitis and tenosynovitis, right upper arm 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 M65.921 be reported with a code from M70.0?
Not as a rule. The Excludes1 note at M65, which applies to M65.921, 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).
