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Atrial fibrillation ICD-10 code

The ICD-10-CM code for atrial fibrillation is I48.91 unspecified atrial fibrillation. It is billable and valid for submission on a claim. There are 14 related codes, and which one you use depends on what the documentation supports.

Also written as afib, a fib, af.

The mistake coders make here

I48.91 (unspecified) is the lazy default. The chart almost always distinguishes paroxysmal (I48.0), persistent (I48.1-), or permanent (I48.2-), and the specific code holds up far better under review.

All ICD-10-CM codes for atrial fibrillation

9 of 14 are billable. Green means you can submit it as-is.

CodeUse it when
I48.91Unspecified atrial fibrillation
I48.0Paroxysmal atrial fibrillation
I48.11Longstanding persistent atrial fibrillation
I48.19Other persistent atrial fibrillation
I48.20Chronic atrial fibrillation, unspecified
I48.21Permanent atrial fibrillation
I48Atrial fibrillation and flutternot billable on its own
I48.2Chronic atrial fibrillationnot billable on its own
I48.1Persistent atrial fibrillationnot billable on its own
I48.9Unspecified atrial fibrillation and atrial flutternot billable on its own
I48.92Unspecified atrial flutter
I48.3Typical atrial flutter
I48.4Atypical atrial flutter
I49.0Ventricular fibrillation and flutternot billable on its own
ICD-10-CMFY2026-Apr· effective April 1, 2026

Codes and descriptions are loaded directly from the CMS/NCHS ICD-10-CM release. The guidance on this page is ours — see our editorial policy. Reference information for professional coders; not medical or billing advice.