ICD-10 Code I21.2 – ST elevation (STEMI) myocardial infarction of other sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I21.2 – ST elevation (STEMI) myocardial infarction of other sites
What it is
This code identifies an acute ST-elevation myocardial infarction affecting sites other than the more commonly specified coronary territories. Use it when the record documents STEMI, but the infarct location is described as other sites.
Clinical signs
Typical findings include ischemic chest pain, ECG evidence of ST elevation, and clinical confirmation of acute myocardial infarction. Clinical features vary; refer to documentation.
When to use this code
Use I21.2 when the provider clearly documents STEMI and the site is recorded as “other” or a nonspecific nonstandard location. It also fits when the infarct location is not one of the separately specified STEMI sites in the chart.
Check documentation if the note names a different STEMI subtype, a non-ST-elevation MI, or an old myocardial infarction. You should code from the provider’s stated diagnosis and infarct location.
Do not use for
Do not use this code for NSTEMI, old MI, or STEMI with a clearly documented specific site that has its own code. Check documentation when the location is unclear.
Coding tip
Confirm both “STEMI” and the infarct site in the provider note before assigning I21.2.