ICD-10-CM 2027 diagnosis code

I27.84Fontan related circulation

Not billable — use a more specific code

I27.84 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code last changed in FY2026 (effective October 1, 2025). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I27.84

I27.84 is the ICD-10-CM diagnosis code for Fontan related circulation. It belongs to category I27 (other pulmonary heart diseases), block I26-I28 (pulmonary heart disease and diseases of pulmonary circulation) and chapter 9 (diseases of the circulatory system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within I27.8 (other specified pulmonary heart diseases), I27.84 is specifically for Fontan related circulation. Related codes cover cor pulmonale (chronic) (I27.81), chronic pulmonary embolism (I27.82), Eisenmenger's syndrome (I27.83) and other specified pulmonary heart diseases (I27.89).

To report this condition, pick the subcode that matches the documentation: I27.840 ([FALD]), I27.841 (dysfunction), I27.848 (condition) and I27.849 (unspecified).

It was added in FY2026, effective October 1, 2025.

Specific codes under I27.84

Notes that apply from higher levels

Instructions written at a parent level also apply to I27.84.

Broader instructions also apply from Chapter 9: Diseases of the circulatory system.

Codes whose notes reference I27.84

Z98Excludes2

Code history

2016
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2021
2022
2023
2024
2025
2026
2027

FY2026 (effective 10/1/2025): Added
No changes since FY2026.

Common questions about I27.84

Is I27.84 billable?: No. I27.84 is a header code. Report one of its more specific subcodes instead.