2026 ICD-10-CM Diagnosis Code E06.5Other chronic thyroiditis
ICD-10-CM Codes›E00–E89›E00-E07›E06
- Billable — Valid for Submission
- Chronic Condition
E06.5 is a billable ICD-10-CM diagnosis code for other chronic thyroiditis. 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. Coders also document this condition as chronic fibrous thyroiditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.
E06.5 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
Code Classification
Medicare Risk Adjustment (HCC)Billing
E06.5 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.
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.
- Chronic fibrous thyroiditis
- Chronic nonsuppurative thyroiditis
- Chronic suppurative thyroiditis
- Chronic thyroiditis
- Hypothyroidism due to fibrous invasive thyroiditis
- Riedel's thyroiditis
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Chronic fibrous thyroiditis
- Chronic thyroiditis NOS
- Ligneous thyroiditis
- Riedel thyroiditis
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Ligneous thyroiditis E06.5
chronic (nonspecific) (sclerosing) E06.5
fibrous E06.5
fibrous (chronic) E06.5
ligneous E06.5
Riedel's E06.5
woody E06.5
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Hashimoto Disease
chronic autoimmune thyroiditis, characterized by the presence of high serum thyroid autoantibodies; goiter; and hypothyroidism.Postpartum Thyroiditis
transient autoimmune thyroiditis occurring in the postpartum period. it is characterized by the presence of high titers of autoantibodies against thyroid peroxidase and thyroglobulin. clinical signs include the triphasic thyroid hormone pattern: beginning with thyrotoxicosis, followed with hypothyroidism, then return to euthyroid state by 1 year postpartum.Thyroiditis
inflammatory diseases of the thyroid gland. thyroiditis can be classified into acute (thyroiditis, suppurative), subacute (granulomatous and lymphocytic), chronic fibrous (riedel's), chronic lymphocytic (hashimoto disease), transient (postpartum thyroiditis), and other autoimmune thyroiditis subtypes.Thyroiditis, Autoimmune
inflammatory disease of the thyroid gland due to autoimmune responses leading to lymphocytic infiltration of the gland. it is characterized by the presence of circulating thyroid antigen-specific t-cells and thyroid autoantibodies. the clinical signs can range from hypothyroidism to thyrotoxicosis depending on the type of autoimmune thyroiditis.Thyroiditis, Subacute
spontaneously remitting inflammatory condition of the thyroid gland, characterized by fever; muscle weakness; sore throat; severe thyroid pain; and an enlarged damaged gland containing giant cells. the disease frequently follows a viral infection.Thyroiditis, Suppurative
acute inflammatory disease of the thyroid gland due to infections by bacteria; fungi; or other microorganisms. symptoms include tender swelling, fever, and often with leukocytosis.
Patient EducationClinical
Thyroid Diseases
Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert E06.5 to ICD-9-CMHistory
Code HistoryHistory
Questions About E06.5Overview
What is the ICD-10 code for other chronic thyroiditis?
The ICD-10-CM code for other chronic thyroiditis is E06.5 (sometimes written as E065). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is E06.5 (Thyroiditis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other chronic thyroiditis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does E06.5 group to?
When other chronic thyroiditis 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.
What is the ICD-9 equivalent of E06.5?
Under the General Equivalence Mappings, other chronic thyroiditis converts to ICD-9-CM 245.3 (chr fibrous thyroiditis) and 245.8 (chr thyroiditis NEC/NOS). The mapping is approximate, so confirm the match fits the documentation.
Does E06.5 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage: E06.5 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 44 (Thyroid Disorders).
