M00.08
BillableStaphylococcal arthritis, vertebrae
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M00.08 an HCC code?
Yes. M00.08 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 M00.08
For M00.08to 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 M00.08 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M00.08 is the ICD-10-CM diagnosis code for staphylococcal arthritis, vertebrae. A bacterial joint infection caused by Staphylococcus bacteria affecting the vertebral joints in the spine. M00.08 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, M00.08 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, M00.08 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.
This code represents spinal involvement; consider if additional codes are needed for specific vertebral levels if documented. Because M00.08 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 M00.08 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code represents spinal involvement; consider if additional codes are needed for specific vertebral levels if documented
- •This condition may also be coded as osteomyelitis if bone involvement is the primary concern
Clinical Significance
Staphylococcal arthritis of the vertebrae represents a serious spinal infection that can lead to vertebral destruction, epidural abscess, and neurological compromise. This condition requires urgent treatment with prolonged intravenous antibiotics and possible surgical intervention to prevent permanent spinal cord damage. The spinal location elevates clinical complexity significantly for risk adjustment purposes.
Documentation Requirements
- ✓Provider documentation identifying Staphylococcus as the causative organism (culture results, clinical diagnosis, or documented species)
- ✓Documentation of the affected joint with specific anatomical site
- ✓Clinical findings supporting joint infection (joint effusion, warmth, erythema, limited range of motion, fever)
- ✓Synovial fluid analysis results or culture and sensitivity reports when available
- ✓Treatment documentation (antibiotics, joint aspiration, surgical drainage/washout)
- ✓Assessment of whether the infection is acute or chronic, and whether it is a primary infection or secondary to another source
- ✓Spinal level(s) involved and any neurological findings documented
Commonly Confused Codes
- •M46.20 — Osteomyelitis of vertebra, unspecified; differs in that osteomyelitis involves bone infection while M00.08 is specifically joint/disc infection
- •M46.30 — Infection of intervertebral disc (pyogenic); overlapping but specifically disc-focused rather than joint-focused
- •M49.80 — Spondylopathy in diseases classified elsewhere; use when spinal involvement is secondary to systemic disease
- •M00.09 — Staphylococcal polyarthritis; use when multiple joints including vertebrae are involved