ICD-10-CM 2027
ICD-10 code for joint effusion
From the official ICD-10-CM alphabetic index entry “Effusion › joint”. Page updated September 29, 2026.
About coding joint effusion
The ICD-10-CM code for joint effusion is M25.40 (Effusion, unspecified joint). The official index lists 9 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M25.40.
Within M25.4, choose M25.40 (unspecified joint) only when documentation doesn't support a more specific option: shoulder (M25.41), elbow (M25.42), wrist (M25.43), hand (M25.44), hip (M25.45), knee (M25.46), ankle and foot (M25.47) and other site (M25.48).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC, relative weight 1.4908), DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC, relative weight 0.9783) and DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC, relative weight 0.7378), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific joint effusion codes (official index)
- ankle M25.47 — Effusion, ankle and foot
- elbow M25.42 — Effusion, elbow
- foot joint M25.47 — Effusion, ankle and foot
- hand joint M25.44 — Effusion, hand
- hip M25.45 — Effusion, hip
- knee M25.46 — Effusion, knee
- shoulder M25.41 — Effusion, shoulder
- specified joint NEC M25.48 — Effusion, other site
- wrist M25.43 — Effusion, wrist
Common questions about joint effusion ICD-10 codes
What is the ICD-10 code for joint effusion?
- M25.40 — Effusion, unspecified joint. More specific codes apply when the documentation supports them: M25.47, M25.42, M25.47, M25.44 and others below.
What is the ICD-10 code for ankle joint effusion?
- M25.47 — Effusion, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for elbow joint effusion?
- M25.42 — Effusion, elbow (header code; choose a more specific subcode).
What is the ICD-10 code for foot joint joint effusion?
- M25.47 — Effusion, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for hand joint joint effusion?
- M25.44 — Effusion, hand (header code; choose a more specific subcode).
What is the ICD-10 code for hip joint effusion?
- M25.45 — Effusion, hip (header code; choose a more specific subcode).
What is the ICD-10 code for knee joint effusion?
- M25.46 — Effusion, knee (header code; choose a more specific subcode).
Is M25.40 billable?
- Yes. M25.40 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M25.40 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M25.40 as a principal diagnosis.
Is M25.40 a CC or MCC?
- No. M25.40 is neither a CC nor an MCC under MS-DRG v44.0.