M13.121
BillableMonoarthritis, not elsewhere classified, right elbow
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M13.121 an HCC code?
No. M13.121 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
M13.121 is the ICD-10-CM diagnosis code for monoarthritis, not elsewhere classified, right elbow. Inflammation of a single joint in the right elbow that doesn't fit into other specific diagnostic categories. M13.121 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).
M13.121 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Confirm documentation specifies right elbow to avoid miscoding as left or unspecified.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M13.121 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm documentation specifies right elbow to avoid miscoding as left or unspecified
- •Ensure the condition is limited to one joint rather than multiple joints