I48 ICD-10-CM Code: Atrial fibrillation and flutter
I48 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
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FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Other forms of heart disease (I30-I5A)
I48
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceAtrial fibrillation and flutter
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for I48. Check the code and parent instructions in the Code Book.
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from I00-I99
- certain infectious and parasitic diseases (A00-B99)Inherited from I00-I99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from I00-I99
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from I00-I99
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from I00-I99
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from I00-I99
- neoplasms (C00-D49)Inherited from I00-I99
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from I00-I99
- systemic connective tissue disorders (M30-M36)Inherited from I00-I99
- transient cerebral ischemic attacks and related syndromes (G45.-)Inherited from I00-I99
Related Codes
Includes
OfficialNo Includes notes are included in this display for I48. Check the code and parent instructions in the Code Book.
Excludes 1
OfficialNo Excludes 1 notes are included in this display for I48. Check the code and parent instructions in the Code Book.
Code First
OfficialNo Code First sequencing instructions are included in this display for I48. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for I48. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for I48. Check the code and parent instructions in the Code Book.
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
- Code
- I48
- Description
- Atrial fibrillation and flutter
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- No
- Payment year
- 2026
Coder workflow notes
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What This Code Means
I48 is the ICD-10-CM diagnosis code for atrial fibrillation and flutter. I48 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering other forms of heart disease (i30-i5a).
Header codes like I48 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for I48 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.