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I20.1

I20.1Angina pectoris with documented spasm

Billable / specific codeICD-10-CM

I20.1 is a billable, specific ICD-10-CM code for angina pectoris with documented spasm. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Angiospastic angina
  • Prinzmetal angina
  • Spasm-induced angina
  • Variant angina

Other codes that can never be billed with I20.1

These codes carry an Excludes1 note pointing at I20.1. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading I20.1 alone.

  • I25.111Atherosclerotic heart disease of native coronary artery with angina pectoris with documented spasm
  • I25.701Atherosclerosis of coronary artery bypass graft(s), unspecified, with angina pectoris with documented spasm
  • I25.711Atherosclerosis of autologous vein coronary artery bypass graft(s) with angina pectoris with documented spasm
  • I25.721Atherosclerosis of autologous artery coronary artery bypass graft(s) with angina pectoris with documented spasm
  • I25.731Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with angina pectoris with documented spasm
  • I25.791Atherosclerosis of other coronary artery bypass graft(s) with angina pectoris with documented spasm

Risk adjustment

I20.1 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

I20.1 is named in 46 Medicare coverage policies 46 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A53775Billing and Coding: Frequency and Duration for Cardiac Rehabilitation and Intensive Cardiac Rehabilitation
  • A56423Billing and Coding: Cardiology Non-emergent Outpatient Stress Testing

How I20.1 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to I20.1.

  • Prinzmetal angina
  • Spasm, spastic, spasticitycardiac
  • Spasm, spastic, spasticitycoronary(artery)
  • Spasm, spastic, spasticityheart
  • Vasospasmcoronary
  • Anginawithdocumented spasm
  • Ischemia, ischemicsupplydue to vasospasm

Related codes at this level

Codes that share I20. If I20.1 is not quite right, the correct code is usually one of these.

Questions about I20.1

Is I20.1 a billable ICD-10-CM code?
Yes. I20.1 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does I20.1 sit in the tabular list?
Diseases of the circulatory system (I00-I99), in the block Ischemic heart diseases (I20-I25).
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.