M00.819
BillableArthritis due to other bacteria, unspecified shoulder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M00.819 an HCC code?
Yes. M00.819 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 M00.819
For M00.819to 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 M00.819 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M00.819 is the ICD-10-CM diagnosis code for arthritis due to other bacteria, unspecified shoulder. Infection and inflammation of the shoulder joint caused by bacteria other than the common ones typically associated with arthritis, when the specific shoulder is not identified. M00.819 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, M00.819 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, M00.819 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.
Verify the causative organism documentation to ensure 'other bacteria' is appropriate; if a specific organism is identified, use a more specific code. Because M00.819 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 M00.819 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Bacterial arthritis of unspecified shoulder represents a serious joint infection requiring urgent antibiotic therapy to prevent joint destruction. The unspecified laterality indicates incomplete documentation that should be clarified for optimal patient care and coding accuracy.
Documentation Requirements
- ✓Specific identification of bacteria as 'other bacteria' (not common organisms)
- ✓Documentation of shoulder joint involvement without laterality specification
- ✓Evidence of bacterial infection through laboratory or clinical findings
- ✓Symptoms of infectious arthritis (pain, swelling, warmth, limited motion)
- ✓Antibiotic or antimicrobial treatment documented
- ✓Exclusion of non-infectious causes of arthritis
- ✓Signs of systemic infection if present
- ✓Attempt to identify specific shoulder affected for future encounters
Commonly Confused Codes
- •M00.811/M00.812 — Same condition but with specific laterality documented
- •M00019 — Staphylococcal arthritis of unspecified shoulder (different organism)
- •M00219 — Streptococcal arthritis of unspecified shoulder (different organism)
- •M06.819 — Other specified rheumatoid arthritis of unspecified shoulder (autoimmune)
- •M19.019 — Primary osteoarthritis of unspecified shoulder (degenerative)