2027 ICD-10-CM Diagnosis Code I27.841Fontan-associated lymphatic dysfunction

ICD-10-CM Codes›I00–I99›I26-I28›I27

ICD-10-CM I27.841
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I27.841 is a billable ICD-10-CM diagnosis code for fontan-associated lymphatic dysfunction. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 808 through 810. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified diseases of veins and lymphatics, Postprocedural or postoperative circulatory system complication, and Pulmonary heart disease.

I27.841 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 191 for payment year 2027.

Code Identity

ICD-10-CM Code
I27.841
Billable Status
Yes — Valid for Submission
Code Describes
Fontan-associated lymphatic dysfunction
Short Description
Fontan-associated lymphatic dysfunction
Same as the full description in the CMS dataset.
Parent Code
I27.84
Fontan related circulation

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI26-I28Pulmonary heart disease and diseases of pulmonary circulation
CategoryI27Other pulmonary heart diseases
This CodeI27.841Fontan-associated lymphatic dysfunction

Medicare Risk Adjustment (HCC)Billing

I27.841 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 191 — Ventricular Septal Defect and Major Congenital Heart Disorders
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I27.841: its own notes plus those printed at Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

  • associated conditions such as:
  • chylothorax (J94.0)
  • Fontan associated protein-losing enteropathy (K90.49)
  • plastic (obstructive) bronchitis (J44.89)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name I27.841, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming I27.841: its condition is not part of those codes, and both may be reported when the patient has both.

  • Z98 Other postprocedural states
    Fontan related circulation (I27.84-) names I27.84-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR039
Other specified diseases of veins and lymphatics
Default principal diagnosis: inpatient No · outpatient No
CCSR CIR038
Postprocedural or postoperative circulatory system complication
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR CIR014
Pulmonary heart disease
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Congenital Heart Defects

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

The full article covers:

  • What are congenital heart defects?
  • What causes congenital heart defects?
  • Who is more likely to have a baby with a congenital heart defect?
  • What are the symptoms of congenital heart defects?
  • What other problems do congenital heart defects cause?
  • How are congenital heart defects diagnosed?
  • What are the treatments for congenital heart defects?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code History & ChangesHistory

Replacement I27.841 replaces the following previously assigned code(s):

  • I27.89 - Other specified pulmonary heart diseases
FY 2026AddedAdded to the ICD-10-CM code setEffective October 1, 2025.
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I27.841Overview

What is the ICD-10 code for fontan-associated lymphatic dysfunction?

The ICD-10-CM code for fontan-associated lymphatic dysfunction is I27.841 (sometimes written as I27841). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I27.841 (Fontan related circulation) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report fontan-associated lymphatic dysfunction on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I27.841 group to?

When fontan-associated lymphatic dysfunction is the principal diagnosis on an inpatient stay, it groups to MS-DRG 808, 809, 810, with relative weights from 1.0749 to 2.1706 depending on complications. Higher weights mean higher Medicare reimbursement.

Does I27.841 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: I27.841 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 191 (Ventricular Septal Defect and Major Congenital Heart Disorders).