B00.82
BillableHerpes simplex myelitis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is B00.82 an HCC code?
Yes. B00.82 maps to Spinal Cord Disorders/Injuries under the CMS-HCC V28 risk adjustment model (and Spinal Cord Disorders/Injuries 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 B00.82
For B00.82 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 B00.82 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
B00.82 is the ICD-10-CM diagnosis code for herpes simplex myelitis. Herpes simplex virus infection affecting the spinal cord, causing inflammation and potentially resulting in weakness or paralysis. B00.82 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering viral infections characterized by skin and mucous membrane lesions (b00-b09).
Under the CMS-HCC V28 risk adjustment model, B00.82 maps to Spinal Cord Disorders/Injuries (HCC 182) with a community, non-dual, aged base RAF weight of 0.282. Under the older V24 model, B00.82 mapped to the same category but with a base RAF weight of 0.464 — 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 the level of spinal cord involvement if specified. Because B00.82 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 B00.82 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the level of spinal cord involvement if specified
- •Distinguish from B01.12 (varicella myelitis) which is caused by chickenpox virus instead
Clinical Significance
Herpes simplex myelitis is inflammation of the spinal cord caused by HSV infection, a rare but serious neurological emergency that can result in paraplegia or quadriplegia. It requires urgent antiviral therapy and reflects significant neurological disease burden in risk adjustment.
Documentation Requirements
- ✓HSV confirmed by CSF PCR (HSV-1 or HSV-2 specified)
- ✓MRI of the spine showing myelitis pattern (T2 signal abnormality within the spinal cord)
- ✓Spinal cord level(s) involved documented (cervical, thoracic, lumbar)
- ✓Neurological examination: motor and sensory level, bowel/bladder function, reflexes
- ✓Immunological status of the patient (immunocompromised vs. immunocompetent)
Commonly Confused Codes
- •B01.12 (Varicella myelitis) — Myelitis from chickenpox virus (VZV), not herpes simplex; different viral etiology with similar presentation
- •B02.24 (Postherpetic myelitis) — Myelitis following herpes zoster (shingles), which is VZV reactivation, not HSV
- •G37.3 (Acute transverse myelitis in demyelinating disease of CNS) — Autoimmune myelitis without viral etiology; HSV myelitis is infection-driven
- •G04.89 (Other myelitis) — Non-specific myelitis; use B00.82 when HSV is the confirmed cause