M01.X19
BillableDirect infection of unspecified shoulder 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.X19 an HCC code?
Yes. M01.X19 maps to Bone/Joint/Muscle 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.X19
For M01.X19to 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.X19 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M01.X19 is the ICD-10-CM diagnosis code for direct infection of unspecified shoulder in infectious and parasitic diseases classified elsewhere. Direct infection of the shoulder joint (side not specified) resulting from an infectious or parasitic disease classified elsewhere. M01.X19 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.X19 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, M01.X19 mapped to the same category but with a base RAF weight of 0.482 — V28 recalibrated weights across the entire model. 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.
Use only when laterality cannot be determined from documentation. Because M01.X19 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.X19 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use only when laterality cannot be determined from documentation
- •Query provider if documentation indicates bilateral involvement; may require two codes
Clinical Significance
This code captures direct joint infection in an unspecified shoulder secondary to classified infectious or parasitic diseases, indicating incomplete documentation of laterality. The condition represents serious joint involvement requiring comprehensive treatment and close monitoring for potential complications including joint destruction.
Documentation Requirements
- ✓Documentation of direct infection involving shoulder joint without laterality specified
- ✓Evidence of underlying infectious or parasitic disease with appropriate A00-B99 code
- ✓Confirmation of direct causation between underlying disease and joint infection
- ✓Clinical manifestations of infectious arthropathy (joint pain, swelling, stiffness)
- ✓Laboratory markers consistent with infection and inflammation
- ✓Radiological evidence of joint involvement or changes
- ✓Microbiology results when joint aspiration performed
- ✓Treatment documentation for both underlying condition and joint manifestation
Commonly Confused Codes
- •M00.919 — Pyogenic arthritis, unspecified shoulder (bacterial infection not from classified disease)
- •M25.519 — Pain in unspecified shoulder (symptom without confirmed infection)
- •M01.X11 — Direct infection of right shoulder in infectious diseases classified elsewhere
- •M01.X12 — Direct infection of left shoulder in infectious diseases classified elsewhere