I60.51
BillableNontraumatic subarachnoid hemorrhage from right vertebral artery
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I60.51 an HCC code?
Yes. I60.51 maps to Intracranial Hemorrhage under the CMS-HCC V28 risk adjustment model (and Intracranial Hemorrhage 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 I60.51
For I60.51to 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 I60.51 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I60.51 is the ICD-10-CM diagnosis code for nontraumatic subarachnoid hemorrhage from right vertebral artery. Bleeding in the space surrounding the brain caused by a rupture of the right vertebral artery, not due to trauma. I60.51 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering cerebrovascular diseases (i60-i69).
Under the CMS-HCC V28 risk adjustment model, I60.51 maps to Intracranial Hemorrhage (HCC 248) with a community, non-dual, aged base RAF weight of 0.239. Under the older V24 model, I60.51 mapped to the same category but with a base RAF weight of 0.230 — 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 documentation specifies the right vertebral artery as the source; if bilateral or unspecified, use different code. Because I60.51 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 I60.51 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies the right vertebral artery as the source; if bilateral or unspecified, use different code
- •This code requires confirmation that the hemorrhage is nontraumatic; traumatic cases use different code series
Clinical Significance
Nontraumatic subarachnoid hemorrhage from the right vertebral artery is a lateralized posterior circulation emergency. The right vertebral artery is a common site for dissection-related hemorrhage, particularly in younger patients. Accurate laterality documentation is essential for endovascular treatment planning and correlating neurological deficits.
Documentation Requirements
- ✓Provider must document nontraumatic subarachnoid hemorrhage from the RIGHT vertebral artery
- ✓Imaging confirmation showing right vertebral artery as source
- ✓Underlying pathology: aneurysm, dissection, or malformation
- ✓Neurological assessment
- ✓Treatment approach: endovascular intervention or surgical management
- ✓Assessment for vertebral artery dominance (which side is larger)
Commonly Confused Codes
- •I60.50 — Nontraumatic subarachnoid hemorrhage from unspecified vertebral artery: unspecified laterality
- •I60.52 — Nontraumatic subarachnoid hemorrhage from left vertebral artery: left side
- •I60.4 — Nontraumatic subarachnoid hemorrhage from basilar artery: different artery in posterior circulation
- •I60.01 — Nontraumatic subarachnoid hemorrhage from right carotid siphon: anterior circulation, not posterior
- •I72.6 — Aneurysm of vertebral artery: unruptured aneurysm without hemorrhage