2026 ICD-10-CM Diagnosis Code E84.0Cystic fibrosis with pulmonary manifestations

ICD-10-CM Codes›E00–E89›E70-E88›E84

ICD-10-CM E84.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E84.0 is a billable ICD-10-CM diagnosis code for cystic fibrosis with pulmonary manifestations. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 177 through 179. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 5 closely related codes. Coders also document this condition as cystic fibrosis of the lung. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cystic fibrosis.

For Medicare Advantage risk adjustment, E84.0 maps to CMS-HCC Category 277 (Cystic Fibrosis) under the V28 model, adding a risk factor of about 0.998 for a community, non-dual, aged beneficiary in payment year 2026.

Code Identity

ICD-10-CM Code
E84.0
Billable Status
Yes — Valid for Submission
Code Describes
Cystic fibrosis with pulmonary manifestations
Short Description
Cystic fibrosis with pulmonary manifestations
Same as the full description in the CMS dataset.
Parent Code
E84
Cystic fibrosis

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE70-E88Metabolic disorders
CategoryE84Cystic fibrosis
This CodeE84.0Cystic fibrosis with pulmonary manifestations

Medicare Risk Adjustment (HCC)Billing

E84.0 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.

CMS-HCC V28 Category (Payment Model)
HCC 277— Cystic Fibrosis
Payment HCC · PY 2026 one of 5 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.998
community, non-dual, aged · ranges 0.650–3.829 across segments
Hierarchy
Superseded by HCC 276
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 110
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 110 · ESRD (V21): HCC 110 · ESRD (V24): HCC 110
ESRD V21 weights: 0.072 dialysis, 0.435–0.494 functioning graft · ESRD V24 weights: 0.125 dialysis, 0.329–3.090 functioning graft
Part D (RxHCC)
RxHCC 225 — Cystic Fibrosis
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2026 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.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cystic fibrosis of the lung

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Use Additional Code

  • code to identify any infectious organism present, such as:
  • Pseudomonas B96.5

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 END012
Cystic fibrosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Calgranulin A

    a 10.8-kda member of the s-100 family of calcium-binding proteins that can form homo- or heterocomplexes with calgranulin b and a variety of other proteins. the calgranulin a/b heterodimer is known as leukocyte l1 antigen complex. calgranulin a is found in many cell types including granulocytes; keratinocytes; and myelomonocytes, and has been shown to act as a chemotactic substance for neutrophils. because it is present in acute inflammation but absent in chronic inflammation, it is a useful biological marker for a number of pathological conditions.

  • Cystic Fibrosis

    an autosomal recessive genetic disease of the exocrine glands. it is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator expressed in several organs including the lung, the pancreas, the biliary system, and the sweat glands. cystic fibrosis is characterized by epithelial secretory dysfunction associated with ductal obstruction resulting in airway obstruction; chronic respiratory infections; pancreatic insufficiency; maldigestion; salt depletion; and heat prostration.

  • Cystic Fibrosis Transmembrane Conductance Regulator

    a chloride channel that regulates secretion in many exocrine tissues. abnormalities in the cftr gene have been shown to cause cystic fibrosis. (hum genet 1994;93(4):364-8)

Patient EducationClinical

Cystic Fibrosis

Cystic fibrosis (CF) is an inherited disease of the mucus and sweat glands. It affects mostly your lungs, pancreas, liver, intestines, sinuses, and sex organs. CF causes your mucus to be thick and sticky. The mucus clogs the lungs, causing breathing problems and making it easy for bacteria to grow.

Read the full article at MedlinePlus

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

Convert E84.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
277.02 Cystic fibros w pul man
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About E84.0Overview

What is the ICD-10 code for cystic fibrosis with pulmonary manifestations?

The ICD-10-CM code for cystic fibrosis with pulmonary manifestations is E84.0 (sometimes written as E840). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is E84.0 (Cystic fibrosis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cystic fibrosis with pulmonary manifestations on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does E84.0 group to?

When cystic fibrosis with pulmonary manifestations is the principal diagnosis on an inpatient stay, it groups to MS-DRG 177, 178, 179, with relative weights from 0.7550 to 1.5627 depending on complications. Higher weights mean higher Medicare reimbursement.

Is E84.0 a CC or MCC?

CMS lists E84.0 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 5 closely related codes in its exclusion list.

What is the ICD-9 equivalent of E84.0?

Under the General Equivalence Mappings, cystic fibrosis with pulmonary manifestations converts to ICD-9-CM 277.02 (cystic fibros w pul man). The mapping is a direct match.

What HCC is E84.0?

E84.0 (cystic fibrosis with pulmonary manifestations) maps to CMS-HCC Category 277 (Cystic Fibrosis), commonly written as HCC 277, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 110 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 225.

Does E84.0 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, E84.0 adds a risk adjustment factor of about 0.998 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.650 to 3.829 depending on the payment segment). A more severe related category (HCC 276) supersedes it when both are reported. See the full factor table on the HCC 277 category page.