M00.862
BillableArthritis due to other bacteria, left knee
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M00.862 an HCC code?
Yes. M00.862 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 M00.862
For M00.862to 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 M00.862 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M00.862 is the ICD-10-CM diagnosis code for arthritis due to other bacteria, left knee. Bacterial infection causing inflammation and swelling in the left knee joint, caused by bacteria other than the most common types. M00.862 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, M00.862 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, M00.862 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.
Ensure the bacterial organism is identified in documentation; if not, use M00.869. Because M00.862 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 M00.862 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure the bacterial organism is identified in documentation; if not, use M00.869
- •Verify left knee laterality is clearly stated in the medical record
Clinical Significance
Bacterial arthritis of the left knee represents a serious threat to mobility and weight-bearing function. This large joint infection can quickly progress to irreversible cartilage damage and requires urgent medical and often surgical intervention to prevent permanent disability.
Documentation Requirements
- ✓Documentation of 'other bacteria' as infectious agent
- ✓Clear specification of left knee joint involvement
- ✓Laboratory confirmation of bacterial infection
- ✓Clinical signs of septic arthritis
- ✓Evidence of appropriate antibiotic therapy
- ✓Assessment of knee function and weight-bearing ability
- ✓Inflammatory markers and joint fluid analysis
- ✓Differentiation from bursitis or ligament injury
Commonly Confused Codes
- •M00062 — Streptococcal arthritis of left knee (different bacterial type)
- •M00016 — Staphylococcal arthritis of left knee (specific organism)
- •M06.862 — Other rheumatoid arthritis of left knee (autoimmune)
- •M17.12 — Unilateral primary osteoarthritis of left knee (degenerative)
- •M70.42 — Prepatellar bursitis of left knee (bursa inflammation)