ICD10BillableValid for clinical use
ICD-10 Code I27.849: Fontan related circulation, unspecified
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).
đź“‹Clinical overview
This ICD-10 code is commonly used when documentation describes pulmonary hypertension. The most accurate code depends on whether the condition is primary or secondary and whether the chart identifies a left-heart, lung-and-hypoxia, chronic-thromboembolic, or other driving mechanism.
When is it used?
- May be used when a clinician documents fontan related circulation, unspecified in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
đź©şClinical context
When commonly used
- Cardiology, pulmonology, inpatient, and utilization-review workflows where pulmonary hypertension affects evaluation, treatment planning, or chronic disease follow-up.
- Coding workflows where the chart identifies primary versus secondary pulmonary hypertension or names the underlying mechanism that changes final code specificity.
Common management context
- Evaluation often includes echocardiography, cardiopulmonary assessment, imaging review, hemodynamic context, and follow-up of the underlying heart, lung, or thromboembolic condition.
- Documentation usually becomes more specific when the chart identifies primary pulmonary hypertension, secondary pulmonary arterial hypertension, left-heart-disease association, lung-disease or hypoxia association, chronic thromboembolic disease, or another secondary pattern.
- Specialist context already linked on this page includes Cardiologist, General Physician.
🔍Key distinctions
Important notes
- This ICD-10 family captures pulmonary-hypertension diagnoses rather than systemic hypertension or unrelated pulmonary disorders without pulmonary-hypertension context.
- Primary versus secondary disease and the documented underlying mechanism both affect final code specificity inside this family.
- This title reflects broad pulmonary-hypertension detail; if the chart clearly identifies primary versus secondary disease or the underlying mechanism, a more specific code may be used.
Related codes to consider
I27.840Fontan-associated liver disease [FALD]
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
I27.841Fontan-associated lymphatic dysfunction
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
I27.848Other Fontan-associated condition
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
Code hierarchy
chapter
9Diseases of the circulatory system (I00-I99)
block
I26-I28Pulmonary heart disease and diseases of pulmonary circulation
category
I27Other pulmonary heart diseases
category
I27.8Other specified pulmonary heart diseases
category
I27.84Fontan related circulation
currentI27.84
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
CardiologistGeneral Physician
Related codes
Sibling codes
Coverage-related procedures and services
CPT 31720high
CATHETER ASPIRATION (SEPARATE PROCEDURE); NASOTRACHEAL
Source: CMS coverage guidance
CPT 94664high
DEMONSTRATION AND/OR EVALUATION OF PATIENT UTILIZATION OF AN AEROSOL GENERATOR, NEBULIZER, METERED DOSE INHALER OR IPPB DEVICE
Source: CMS coverage guidance
HCPCS J0153high
INJECTION, ADENOSINE, 1 MG (NOT TO BE USED TO REPORT ANY ADENOSINE PHOSPHATE COMPOUNDS)
Source: CMS coverage guidance
HCPCS J1245high
INJECTION, DIPYRIDAMOLE, PER 10 MG
Source: CMS coverage guidance
HCPCS J1250high
INJECTION, DOBUTAMINE HYDROCHLORIDE, PER 250 MG
Source: CMS coverage guidance
CPT 94640high
PRESSURIZED OR NONPRESSURIZED INHALATION TREATMENT FOR ACUTE AIRWAY OBSTRUCTION FOR THERAPEUTIC PURPOSES AND/OR FOR DIAGNOSTIC PURPOSES SUCH AS SPUTUM INDUCTION WITH AN AEROSOL GENERATOR, NEBULIZER, METERED DOSE INHALER OR INTERMITTENT POSITIVE PRESSURE BREATHING (IPPB) DEVICE
Source: CMS coverage guidance
Coding guidelines
Common synonyms
Fontan related circulation, unspecifiedFontan related circulation
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.