ICD10BillableValid for clinical use
ICD-10 Code I20.0: Unstable angina
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).
When is it used?
- May be used when a clinician documents unstable angina in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
Code hierarchy
chapter
9Diseases of the circulatory system (I00-I99)
block
I20-I25Ischemic heart diseases
category
I20Angina pectoris
currentI20
Official coding notes
Inclusion terms
- Accelerated angina
- Crescendo angina
- De novo effort angina
- Intermediate coronary syndrome
- Preinfarction syndrome
- Worsening effort angina
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
CardiologistGeneral Physician
Related codes
Sibling codes
Coverage-related procedures and services
CPT 93350high
ECHOCARDIOGRAPHY, TRANSTHORACIC, REAL-TIME WITH IMAGE DOCUMENTATION (2D), INCLUDES M-MODE RECORDING, WHEN PERFORMED, DURING REST AND CARDIOVASCULAR STRESS TEST USING TREADMILL, BICYCLE EXERCISE AND/OR PHARMACOLOGICALLY INDUCED STRESS, WITH INTERPRETATION AND REPORT;
Source: CMS coverage guidance
CPT 93351high
ECHOCARDIOGRAPHY, TRANSTHORACIC, REAL-TIME WITH IMAGE DOCUMENTATION (2D), INCLUDES M-MODE RECORDING, WHEN PERFORMED, DURING REST AND CARDIOVASCULAR STRESS TEST USING TREADMILL, BICYCLE EXERCISE AND/OR PHARMACOLOGICALLY INDUCED STRESS, WITH INTERPRETATION AND REPORT; INCLUDING PERFORMANCE OF CONTINUOUS ELECTROCARDIOGRAPHIC MONITORING, WITH SUPERVISION BY A PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL
Source: CMS coverage guidance
CPT 93241high
EXTERNAL ELECTROCARDIOGRAPHIC RECORDING FOR MORE THAN 48 HOURS UP TO 7 DAYS BY CONTINUOUS RHYTHM RECORDING AND STORAGE; INCLUDES RECORDING, SCANNING ANALYSIS WITH REPORT, REVIEW AND INTERPRETATION
Source: CMS coverage guidance
CPT 93242high
EXTERNAL ELECTROCARDIOGRAPHIC RECORDING FOR MORE THAN 48 HOURS UP TO 7 DAYS BY CONTINUOUS RHYTHM RECORDING AND STORAGE; RECORDING (INCLUDES CONNECTION AND INITIAL RECORDING)
Source: CMS coverage guidance
CPT 93244high
EXTERNAL ELECTROCARDIOGRAPHIC RECORDING FOR MORE THAN 48 HOURS UP TO 7 DAYS BY CONTINUOUS RHYTHM RECORDING AND STORAGE; REVIEW AND INTERPRETATION
Source: CMS coverage guidance
CPT 93243high
EXTERNAL ELECTROCARDIOGRAPHIC RECORDING FOR MORE THAN 48 HOURS UP TO 7 DAYS BY CONTINUOUS RHYTHM RECORDING AND STORAGE; SCANNING ANALYSIS WITH REPORT
Source: CMS coverage guidance
Mapped diagnoses and classifications
SNOMED_CT 59021001high
Angina decubitus
Source: SNOMED International ICD-10 map
SNOMED_CT 25106000high
Impending infarction
Source: SNOMED International ICD-10 map
SNOMED_CT 4557003high
Preinfarction syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 15960741000119103high
Preinfarction syndrome due to arteriosclerosis of nonautologous biological coronary artery bypass graft
Source: SNOMED International ICD-10 map
SNOMED_CT 15960861000119108high
Preinfarction syndrome due to coronary arteriosclerosis in artery of transplanted heart
Source: SNOMED International ICD-10 map
SNOMED_CT 15960661000119107high
Unstable angina co-occurrent and due to arteriosclerosis of coronary artery bypass graft
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy and official ICD code match exactly.
Legacy codes
I20.0
Common synonyms
Unstable angina
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.