M02.80
BillableOther reactive arthropathies, unspecified site
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M02.80 an HCC code?
Yes. M02.80 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 M02.80
For M02.80to 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 M02.80 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M02.80 is the ICD-10-CM diagnosis code for other reactive arthropathies, unspecified site. Joint inflammation caused by a reaction to infection elsewhere in the body, affecting an unspecified location. M02.80 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, M02.80 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, M02.80 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.
This is a catch-all code; use more specific codes (M02.81-M02.89) when the joint site is documented. Because M02.80 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 M02.80 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Other reactive arthropathies of unspecified site represents joint inflammation caused by bacterial infection elsewhere in the body when the specific joint location cannot be determined. This condition requires ongoing management and carries moderate risk adjustment value due to its chronic inflammatory nature and treatment requirements.
Documentation Requirements
- ✓Documented diagnosis of reactive arthropathy with unspecified joint location
- ✓Evidence of precipitating bacterial infection
- ✓Clinical findings supporting inflammatory arthritis
- ✓Laboratory evidence of systemic inflammation
- ✓Assessment of functional limitations despite unspecified location
- ✓Treatment plan with anti-inflammatory medications
- ✓Exclusion of other specific arthropathies
- ✓Documentation explaining why joint location cannot be specified
Commonly Confused Codes
- •M13.10 — Monoarthritis, not elsewhere classified, unspecified site lacks infectious trigger
- •M19.90 — Unspecified osteoarthritis, unspecified site represents degenerative disease
- •M25.50 — Pain in unspecified joint is symptomatic rather than diagnostic
- •M79.9 — Soft tissue disorder, unspecified affects soft tissues rather than joints