2026 ICD-10-CM Diagnosis Code I26.01Septic pulmonary embolism with acute cor pulmonale

ICD-10-CM Codes›I00–I99›I26-I28›I26

ICD-10-CM I26.01
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I26.01 is a billable ICD-10-CM diagnosis code for septic pulmonary embolism with acute cor pulmonale. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 175 through 176. The code is not accepted as a principal diagnosis by the Medicare Code Editor. Coders also document this condition as acute cor pulmonale. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute pulmonary embolism.

Code Identity

ICD-10-CM Code
I26.01
Billable Status
Yes — Valid for Submission
Code Describes
Septic pulmonary embolism with acute cor pulmonale
Short Description
Septic pulmonary embolism with acute cor pulmonale
Same as the full description in the CMS dataset.
Parent Code
I26.0
Pulmonary embolism with acute cor pulmonale

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI26-I28Pulmonary heart disease and diseases of pulmonary circulation
CategoryI26Pulmonary embolism
This CodeI26.01Septic pulmonary embolism with acute cor pulmonale

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I26.01.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute cor pulmonale
  • Acute cor pulmonale due to septic pulmonary embolism
  • Acute pulmonary embolism
  • Cor pulmonale
  • Right ventricular failure due to pulmonary vascular disease
  • Septic embolus of artery
  • Septic pulmonary embolism

Tabular List NotesGuidance

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

Code First

  • underlying infection

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Embolism(multiple) (paradoxical)
      • pulmonary (acute) (artery) (vein)
        • septic
          • with acute cor pulmonale

Clinical ClassificationClinical

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

CCSR CIR013
Acute pulmonary embolism
Default principal diagnosis: inpatient No · outpatient Yes

Clinical InformationClinical

  • Acute Pulmonary Embolism

    an acute embolism to the pulmonary vasculature.

Patient EducationClinical

Pulmonary Embolism

A pulmonary embolism (PE) is a sudden blockage in a lung artery. It usually happens when a blood clot breaks loose and travels through the bloodstream to the lungs. PE is a serious condition that can cause:

The full article covers:

  • What is a pulmonary embolism (PE)?
  • What causes a pulmonary embolism (PE)?
  • Who is more likely to develop a pulmonary embolism (PE)?
  • What are the symptoms of a pulmonary embolism (PE)?
  • How is a pulmonary embolism (PE) diagnosed?
  • What are the treatments for a pulmonary embolism (PE)?
  • Can pulmonary embolism (PE) be prevented?

Read the full article at MedlinePlus

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

Convert I26.01 to ICD-9-CMHistory

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

ICD-9-CM
415.12 Septic pulmonary embolsm
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
415.0 Acute cor pulmonale
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 I26.01Overview

Is I26.01 (Pulmonary embolism with acute cor pulmonale) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report septic pulmonary embolism with acute cor pulmonale on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I26.01 group to?

On inpatient claims, septic pulmonary embolism with acute cor pulmonale maps to MS-DRG 175, 176, with relative weights from 0.8050 to 1.3736 depending on complications. Higher weights mean higher Medicare reimbursement.

Can I26.01 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because septic pulmonary embolism with acute cor pulmonale describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

What is the ICD-9 equivalent of I26.01?

Under the General Equivalence Mappings, septic pulmonary embolism with acute cor pulmonale converts to ICD-9-CM 415.12 (septic pulmonary embolsm) and 415.0 (acute cor pulmonale). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.