M13.179
BillableMonoarthritis, not elsewhere classified, unspecified ankle and foot
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M13.179 an HCC code?
No. M13.179 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
M13.179 is the ICD-10-CM diagnosis code for monoarthritis, not elsewhere classified, unspecified ankle and foot. Inflammation of a single joint in the ankle or foot area where the specific side (left or right) is not documented. M13.179 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).
M13.179 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.
This is a less specific code; use only when laterality cannot be determined from documentation.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M13.179 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a less specific code; use only when laterality cannot be determined from documentation
- •Query the provider if possible to determine whether the condition affects the right or left ankle/foot for more specific coding