M25.4 vs M65.1

M25.4 (Effusion of joint) compared with M65.1 (Other infective (teno)synovitis), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.

Can these codes be reported together?

No — do not report together. M25.4 carries an Excludes1 note covering M65.1: “other infective (teno)synovitis (M65.1-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Side by side

	M25.4Effusion of joint	M65.1Other infective (teno)synovitis
Billing status	Non-billable header Report instead: M25.40, M25.411, M25.412, M25.419, M25.421	Non-billable header Report instead: M65.10, M65.111, M65.112, M65.119, M65.121
Classification	M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)	M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
Definition	Effusion of joint is a non-billable ICD-10-CM category code (M25.4).	Other infective (teno)synovitis is a non-billable ICD-10-CM category code (M65.1).

Edit this comparison Check a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources