I60.12
BillableNontraumatic subarachnoid hemorrhage from left middle cerebral artery
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I60.12 an HCC code?
Yes. I60.12 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 I60.12
For I60.12to 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 I60.12 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I60.12 is the ICD-10-CM diagnosis code for nontraumatic subarachnoid hemorrhage from left middle cerebral artery. Sudden bleeding in the space around the brain from a ruptured left middle cerebral artery, not caused by trauma. I60.12 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, I60.12 maps to Intracranial Hemorrhage (HCC 248) with a community, non-dual, aged base RAF weight of 0.239. Under the older V24 model, I60.12 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.
The middle cerebral artery is the most common site for subarachnoid hemorrhage; confirm left-sided location in documentation. Because I60.12 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 I60.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The middle cerebral artery is the most common site for subarachnoid hemorrhage; confirm left-sided location in documentation
- •This is a life-threatening emergency requiring immediate intervention
Clinical Significance
Nontraumatic subarachnoid hemorrhage from the left middle cerebral artery is particularly significant because the left hemisphere is dominant for language in most patients. Rupture here frequently causes aphasia and right-sided hemiplegia in addition to the general effects of subarachnoid hemorrhage. This carries substantial rehabilitation needs and long-term disability.
Documentation Requirements
- ✓Provider must document nontraumatic subarachnoid hemorrhage from the LEFT middle cerebral artery
- ✓Imaging confirmation showing left-sided hemorrhage source
- ✓Aneurysm characteristics and treatment approach
- ✓Neurological assessment — especially speech and language function
- ✓Severity grading
- ✓Rehabilitation plan given likely dominant hemisphere involvement
Commonly Confused Codes
- •I60.10 — Nontraumatic subarachnoid hemorrhage from unspecified middle cerebral artery: unspecified laterality
- •I60.11 — Nontraumatic subarachnoid hemorrhage from right middle cerebral artery: right side
- •I60.02 — Nontraumatic subarachnoid hemorrhage from left carotid siphon: different artery
- •I61.1 — Nontraumatic intracerebral hemorrhage in hemisphere, cortical: intraparenchymal bleeding
- •I63.312 — Cerebral infarction due to thrombosis of left middle cerebral artery: ischemic, not hemorrhagic