MCMCB Pro
I66.03

I66.03Occlusion and stenosis of bilateral middle cerebral arteries

Billable / specific codeICD-10-CMbilateral

I66.03 is a billable, specific ICD-10-CM code for occlusion and stenosis of bilateral middle cerebral arteries. It is valid for submission on a claim.

Risk adjustment

I66.03 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

I66.03 is named in 51 Medicare coverage policies 51 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A52868Billing and Coding: Transesophageal Echocardiography (TEE)
  • A52992Billing and Coding: Non-Invasive Cerebrovascular Arterial Studies
  • A52992Billing and Coding: Non-Invasive Cerebrovascular Arterial Studies
  • A56423Billing and Coding: Cardiology Non-emergent Outpatient Stress Testing

Related codes at this level

Codes that share I66.0. If I66.03 is not quite right, the correct code is usually one of these.

Questions about I66.03

Is I66.03 a billable ICD-10-CM code?
Yes. I66.03 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does I66.03 sit in the tabular list?
Diseases of the circulatory system (I00-I99), in the block Cerebrovascular diseases (I60-I69).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.