2026 ICD-10-CM Diagnosis Code E05.41Thyrotoxicosis factitia with thyrotoxic crisis or storm

ICD-10-CM Codes›E00–E89›E00-E07›E05

ICD-10-CM E05.41
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E05.41 is a billable ICD-10-CM diagnosis code for thyrotoxicosis factitia with thyrotoxic crisis or storm. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 643 through 645. 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 59 closely related codes. Coders also document this condition as thyrotoxic crisis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.

E05.41 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 44 for payment year 2026.

Code Identity

ICD-10-CM Code
E05.41
Billable Status
Yes — Valid for Submission
Code Describes
Thyrotoxicosis factitia with thyrotoxic crisis or storm
Short Description
Thyrotoxicosis factitia with thyrotoxic crisis or storm
Same as the full description in the CMS dataset.
Parent Code
E05.4
Thyrotoxicosis factitia

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE00-E07Disorders of thyroid gland
CategoryE05Thyrotoxicosis [hyperthyroidism]
This CodeE05.41Thyrotoxicosis factitia with thyrotoxic crisis or storm

Medicare Risk Adjustment (HCC)Billing

E05.41 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 44 — Thyroid Disorders
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.

  • Thyrotoxic crisis
  • Thyrotoxicosis factitia
  • Thyrotoxicosis factitia with thyrotoxic crisis

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 END001
Thyroid disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Hyperthyroidism

Hyperthyroidism, or overactive thyroid, happens when your thyroid gland makes more thyroid hormones than your body needs.

The full article covers:

  • What is hyperthyroidism?
  • What causes hyperthyroidism?
  • Who is at risk for hyperthyroidism?
  • What are the symptoms of hyperthyroidism?
  • What other problems can hyperthyroidism cause?
  • How is hyperthyroidism diagnosed?
  • What are the treatments for hyperthyroidism?

Read the full article at MedlinePlus

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

Convert E05.41 to ICD-9-CMHistory

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

ICD-9-CM
242.81 Thyrotox orig NEC w cris
Approximate The match is approximate rather than exact.

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 E05.41Overview

What is the ICD-10 code for thyrotoxicosis factitia with thyrotoxic crisis or storm?

The ICD-10-CM code for thyrotoxicosis factitia with thyrotoxic crisis or storm is E05.41 (sometimes written as E0541). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is E05.41 (Thyrotoxicosis factitia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report thyrotoxicosis factitia with thyrotoxic crisis or storm on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does E05.41 group to?

When thyrotoxicosis factitia with thyrotoxic crisis or storm is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 643, 644, 645, with relative weights from 0.7683 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.

Is E05.41 a CC or MCC?

CMS lists E05.41 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 59 closely related codes in its exclusion list.

What is the ICD-9 equivalent of E05.41?

Under the General Equivalence Mappings, thyrotoxicosis factitia with thyrotoxic crisis or storm converts to ICD-9-CM 242.81 (thyrotox orig NEC w cris). The mapping is approximate, so confirm the match fits the documentation.

Does E05.41 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: E05.41 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 44 (Thyroid Disorders).