M01.X71
BillableDirect infection of right ankle and foot in infectious and parasitic diseases classified elsewhere
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M01.X71 an HCC code?
Yes. M01.X71 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for M01.X71
For M01.X71to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M01.X71 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M01.X71 is the ICD-10-CM diagnosis code for direct infection of right ankle and foot in infectious and parasitic diseases classified elsewhere. Joint infection in the right ankle and foot caused by an infectious disease classified elsewhere, such as tuberculosis or a parasitic infection. M01.X71 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering infectious arthropathies (m00-m02).
Under the CMS-HCC V28 risk adjustment model, M01.X71 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.479. Under the older CMS-HCC V24 model, M01.X71 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 39) with a community, non-dual, aged base RAF weight of 0.401. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Always pair this code with a secondary diagnosis code identifying the underlying infectious or parasitic disease. Because M01.X71 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M01.X71 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always pair this code with a secondary diagnosis code identifying the underlying infectious or parasitic disease
- •The 'X' in the code indicates the site is specified elsewhere; ensure laterality (right) is clearly documented
Clinical Significance
Direct infection of the right ankle and foot joints secondary to classified infectious or parasitic diseases represents a complex condition affecting mobility and weight-bearing function. The multiple small joints in the foot and ankle make this diagnosis particularly challenging for treatment and functional preservation.
Documentation Requirements
- ✓Clear documentation of right ankle and foot joint infection
- ✓Primary diagnosis code for underlying infectious or parasitic disease
- ✓Evidence of direct relationship between systemic infection and ankle/foot involvement
- ✓Physical examination documenting ankle and foot inflammation and functional impairment
- ✓Laboratory studies supporting infectious process and systemic involvement
- ✓Imaging studies confirming ankle and foot joint involvement
- ✓Joint aspiration results when performed on accessible joints
- ✓Treatment plan addressing both underlying disease and foot/ankle-specific therapy
Commonly Confused Codes
- •M00.971 — Pyogenic arthritis, right ankle and foot (bacterial infection not from classified disease)
- •M25.571 — Pain in right ankle and foot (joint pain without infectious etiology)
- •M01.X72 — Direct infection of left ankle and foot in infectious diseases classified elsewhere
- •L03.116 — Cellulitis of right lower limb (soft tissue infection without joint involvement)