I60.52
BillableNontraumatic subarachnoid hemorrhage from left vertebral artery
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I60.52 an HCC code?
Yes. I60.52 maps to Cerebral 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 I60.52
For I60.52to 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 I60.52 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I60.52 is the ICD-10-CM diagnosis code for nontraumatic subarachnoid hemorrhage from left vertebral artery. Bleeding in the space surrounding the brain caused by a rupture of the left vertebral artery, not due to trauma. I60.52 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, I60.52 maps to Cerebral Hemorrhage (HCC 248) with a community, non-dual, aged base RAF weight of 0.289. Under the older CMS-HCC V24 model, I60.52 maps to Intracranial Hemorrhage (HCC 99) with a community, non-dual, aged base RAF weight of 0.262. 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 documentation clearly identifies the left vertebral artery as the bleeding source. Because I60.52 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 I60.52 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure documentation clearly identifies the left vertebral artery as the bleeding source
- •Distinguish from right-sided hemorrhage (I60.51) and bilateral cases which require separate coding
Clinical Significance
Nontraumatic subarachnoid hemorrhage from the left vertebral artery is a lateralized posterior circulation hemorrhage. The left vertebral artery is the dominant artery in approximately 50% of patients, making hemorrhage from this vessel potentially more devastating when it is the dominant supply. Treatment planning must account for this anatomical consideration.
Documentation Requirements
- ✓Provider must document nontraumatic subarachnoid hemorrhage from the LEFT vertebral artery
- ✓Imaging confirmation of left vertebral artery as hemorrhage source
- ✓Vertebral artery dominance assessment
- ✓Underlying pathology and its characterization
- ✓Neurological assessment
- ✓Treatment plan considering dominance and collateral circulation
Commonly Confused Codes
- •I60.50 — Nontraumatic subarachnoid hemorrhage from unspecified vertebral artery: unspecified laterality
- •I60.51 — Nontraumatic subarachnoid hemorrhage from right vertebral artery: right side
- •I60.4 — Nontraumatic subarachnoid hemorrhage from basilar artery: downstream from vertebral arteries
- •I60.02 — Nontraumatic subarachnoid hemorrhage from left carotid siphon: anterior circulation
- •I67.0 — Dissection of cerebral arteries, nonruptured: dissection without hemorrhage