I60.9
BillableNontraumatic subarachnoid hemorrhage, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I60.9 an HCC code?
Yes. I60.9 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 I60.9
For I60.9to 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 I60.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I60.9 is the ICD-10-CM diagnosis code for nontraumatic subarachnoid hemorrhage, unspecified. Bleeding in the space surrounding the brain from an unknown or unspecified nontraumatic source. I60.9 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, I60.9 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, I60.9 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.
Use only when the source artery is not documented or cannot be determined from available records. Because I60.9 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 I60.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use only when the source artery is not documented or cannot be determined from available records
- •Query the provider if possible to obtain more specific artery information for more accurate coding
Clinical Significance
Nontraumatic subarachnoid hemorrhage is a life-threatening neurological emergency with high mortality and morbidity rates. It is critical for risk adjustment because it reflects severe acute cerebrovascular disease requiring intensive care, surgical intervention, and long-term follow-up. Accurate capture ensures appropriate resource allocation for these high-acuity patients.
Documentation Requirements
- ✓Confirmation of nontraumatic etiology (exclude trauma-related causes)
- ✓Imaging results (CT scan or lumbar puncture) confirming subarachnoid hemorrhage
- ✓Clinical presentation including sudden severe headache, altered consciousness, or focal neurological deficits
- ✓Statement that the specific source artery could not be identified
- ✓Treatment plan including neurosurgical consultation and management approach
- ✓Assessment of Hunt and Hess grade or World Federation of Neurological Surgeons scale if available
Commonly Confused Codes
- •I60.0-I60.8 — Subarachnoid hemorrhage from specific arteries; use when the source artery is identified
- •I61.9 — Nontraumatic intracerebral hemorrhage; bleeding is within brain tissue, not in the subarachnoid space
- •S06.6X — Traumatic subarachnoid hemorrhage; use when caused by head injury or trauma
- •I62.9 — Nontraumatic intracranial hemorrhage, unspecified; a broader category that includes all intracranial bleeding types