A02.23
BillableSalmonella arthritis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A02.23 an HCC code?
Yes. A02.23 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 A02.23
For A02.23 to 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 A02.23 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
A02.23 is the ICD-10-CM diagnosis code for salmonella arthritis. This is a joint infection caused by Salmonella bacteria, which can cause inflammation, pain, and swelling in one or more joints. It typically develops as a complication of Salmonella food poisoning or other Salmonella infections in the body. A02.23 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).
Under the CMS-HCC V28 risk adjustment model, A02.23 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, A02.23 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.
Verify that the documentation confirms Salmonella as the causative organism of the arthritis; do not assume arthritis is Salmonella-related without explicit confirmation. Because A02.23 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 A02.23 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the documentation confirms Salmonella as the causative organism of the arthritis; do not assume arthritis is Salmonella-related without explicit confirmation
- •Identify and code the specific joint(s) affected using the appropriate anatomical site codes, as A02.23 requires a fifth character to specify the site of arthritis
Clinical Significance
Salmonella arthritis represents direct joint infection by non-typhi Salmonella organisms, a condition particularly associated with sickle cell disease and immunocompromised states. Prompt diagnosis and treatment are critical to prevent permanent joint damage and systemic spread.
Documentation Requirements
- ✓Identification of Salmonella species from synovial fluid culture or strong clinical evidence
- ✓Specific joint(s) involved with physical examination findings
- ✓Synovial fluid analysis (cell count, Gram stain, culture results)
- ✓Imaging of affected joints if obtained
- ✓Documentation of predisposing conditions (sickle cell disease, HIV, immunosuppressive therapy)
Commonly Confused Codes
- •A01.04 (Typhoid arthritis) — Use A01.04 specifically for S. typhi joint infection; A02.23 is for non-typhi Salmonella species
- •M00.9 (Pyogenic arthritis, unspecified) — Use A02.23 when Salmonella is identified as the causative organism
- •M02.19 (Postdysenteric arthropathy) — Use M02 series for reactive arthritis following Salmonella GI infection, not A02.23 which is for direct infectious arthritis