M00.29
BillableOther streptococcal polyarthritis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M00.29 an HCC code?
Yes. M00.29 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 M00.29
For M00.29to 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 M00.29 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M00.29 is the ICD-10-CM diagnosis code for other streptococcal polyarthritis. A bacterial infection caused by streptococcus bacteria affecting multiple joints throughout the body simultaneously. M00.29 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, M00.29 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, M00.29 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.
Document all affected joints in the medical record for comprehensive clinical understanding. Because M00.29 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 M00.29 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document all affected joints in the medical record for comprehensive clinical understanding
- •This polyarthritis pattern may indicate systemic infection requiring broader treatment approach
Clinical Significance
Septic polyarthritis caused by non-pneumococcal streptococcal organisms indicates disseminated hematogenous bacterial spread affecting multiple joints simultaneously, representing a serious systemic infection with high morbidity. This condition requires aggressive intravenous antibiotic therapy and often surgical drainage of multiple joints, with significant risk for permanent joint destruction and sepsis. Risk adjustment captures this as a high-acuity infectious condition reflecting substantial ongoing healthcare resource utilization.
Documentation Requirements
- ✓Provider documentation explicitly stating streptococcal septic arthritis or pyogenic arthritis with identified causative organism
- ✓Synovial fluid analysis results (cell count, Gram stain, crystal analysis to rule out gout/pseudogout)
- ✓Culture and sensitivity results identifying the specific streptococcal organism, or clinical rationale if culture-negative
- ✓Clinical signs and symptoms of joint infection (acute onset joint pain, swelling, warmth, erythema, fever, limited range of motion)
- ✓Documentation of multiple specific joints affected with evidence of bacterial involvement in each
- ✓Blood cultures and evaluation for endocarditis or other sources of hematogenous spread
- ✓Treatment plan including antibiotic regimen, duration, and any surgical intervention (arthrocentesis, irrigation and debridement, arthroscopy)
Commonly Confused Codes
- •M00.1x (Pneumococcal arthritis) — Use M00.1x when the causative organism is specifically Streptococcus pneumoniae; M00.2x covers Group A, Group B, and other non-pneumococcal streptococcal species
- •M00.8x (Arthritis due to other bacteria) — Use M00.8x for septic arthritis caused by non-streptococcal organisms such as Staphylococcus, Escherichia coli, or Pseudomonas
- •M00.0x (Staphylococcal arthritis) — Staphylococcal joint infections use M00.0x; do not confuse with streptococcal infections which use M00.2x
- •M02.x (Reactive arthropathies) — Reactive arthritis is post-infectious and sterile; polyarthritis codes in M00 require active bacterial infection in the joints, not a post-infectious immune response