I48.91
✓ Billable
Unspecified atrial fibrillation
ICD-10-CM · FY2026 · Diseases of the Circulatory System
Code
I48.91
System
ICD-10-CM
Billable
Yes — valid for submission
Effective
FY2026
Chapter
Diseases of the Circulatory System
Source
CMS / CDC NCHS
⚠ Verify before billing. Confirm against the current CMS/NCHS ICD-10-CM files and your payer's rules before claims submission.
Frequently asked questions
What is ICD-10 code I48.91?
ICD-10-CM code I48.91 represents Unspecified atrial fibrillation. It is a billable diagnosis code in the Diseases of the Circulatory System chapter, effective October 1, 2025 – September 30, 2026.
Is I48.91 billable?
Yes. I48.91 is a valid billable ICD-10-CM code for insurance claims and clinical documentation.
What chapter is I48.91 in?
I48.91 belongs to the Diseases of the Circulatory System chapter (I00–I99) of ICD-10-CM.
Related codes in the I48 category
I48
Atrial fibrillation and flutter
Non-billable
I48.0
Paroxysmal atrial fibrillation
Billable
I48.1
Persistent atrial fibrillation
Non-billable
I48.2
Chronic atrial fibrillation
Non-billable
I48.3
Typical atrial flutter
Billable
I48.4
Atypical atrial flutter
Billable
I48.9
Unspecified atrial fibrillation and atrial flutter
Non-billable
I48.11
Longstanding persistent atrial fibrillation
Billable
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