I23 ICD-10-CM Code: Certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Ischemic heart diseases (I20-I25)
I23
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceCertain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)
Certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for I23 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for I23 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I23 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I23 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for I23 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I23 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I23 in this effective period.
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
What This Code Means
I23 is the ICD-10-CM diagnosis code for certain current complications following st elevation (stemi) and non-st elevation (nstemi) myocardial infarction (within the 28 day period). I23 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering ischemic heart diseases (i20-i25).
Header codes like I23 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at I23's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I23 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.