M01.X22
BillableDirect infection of left elbow 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.X22 an HCC code?
Yes. M01.X22 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.X22
For M01.X22to 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.X22 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M01.X22 is the ICD-10-CM diagnosis code for direct infection of left elbow in infectious and parasitic diseases classified elsewhere. Direct infection of the left elbow joint resulting from an infectious or parasitic disease classified elsewhere. M01.X22 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.X22 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.X22 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.
This is a manifestation code requiring a primary infectious disease diagnosis. Because M01.X22 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.X22 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a manifestation code requiring a primary infectious disease diagnosis
- •Verify left elbow is specifically documented in the medical record
Clinical Significance
Direct infection of the left elbow joint resulting from infectious or parasitic diseases classified elsewhere represents a serious complication requiring immediate intervention. This condition can lead to significant functional impairment and joint destruction if not promptly and adequately treated with appropriate antimicrobial therapy.
Documentation Requirements
- ✓Documentation specifying left elbow joint as site of infection
- ✓Primary diagnosis code for underlying infectious or parasitic disease
- ✓Evidence of direct relationship between systemic infection and joint involvement
- ✓Clinical assessment documenting elbow joint inflammation and dysfunction
- ✓Laboratory studies supporting infectious process (CBC, ESR, CRP, procalcitonin)
- ✓Radiographic studies demonstrating joint involvement or complications
- ✓Synovial fluid analysis if joint aspiration performed
- ✓Comprehensive treatment plan for both systemic and local infection
Commonly Confused Codes
- •M00.922 — Pyogenic arthritis, left elbow (routine bacterial joint infection)
- •M25.522 — Pain in left elbow (joint pain without confirmed infection)
- •M01.X21 — Direct infection of right elbow in infectious diseases classified elsewhere
- •M02.222 — Postimmunization arthropathy, left elbow (vaccine-related joint reaction)