What is ICD-10 code E01.0?

E01.0 is the ICD-10-CM diagnosis code for Iodine-deficiency related diffuse (endemic) goiter. An enlarged thyroid gland (goiter) that develops in areas with low iodine in the diet, affecting the entire thyroid uniformly rather than forming nodules. E01.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E01.0 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E01.0 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E01.0 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does E01.0 map to under V28?

E01.0 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for E01.0?

E01.0 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for E01.0?

E01.0 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports E01.0?

Document the geographic region or endemic area when possible, as this helps establish the iodine-deficiency etiology Distinguish from multinodular goiter (E01.1) by confirming the goiter is diffuse rather than nodular E01.0 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

2026 ICD-10-CM E01.0: Iodine-deficiency related diffuse

E01.0 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupE01.0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of thyroid gland (E00-E07)

E01.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Iodine-deficiency related diffuse (endemic) goiter

An enlarged thyroid gland (goiter) that develops in areas with low iodine in the diet, affecting the entire thyroid uniformly rather than forming nodules.

Buddy Insight

Iodine-deficiency related diffuse (endemic) goiter represents thyroid enlargement due to chronic iodine deficiency in geographic regions where iodine intake is insufficient.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 44

Thyroid Disorders

Code-level coefficient reference

Code Book Path

Official

E01Iodine-deficiency related thyroid disorders and allied conditions

E01.0Iodine-deficiency related diffuse (endemic) goiter

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E01.0 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E01.0 in this effective period.

Related Child Codes

Official

E01.1Iodine-deficiency related multinodular (endemic) goiter

E01.2Iodine-deficiency related (endemic) goiter, unspecified

E01.8Other iodine-deficiency related thyroid disorders and allied conditions

Includes

Official

ICD-10-CM does not list Includes notes for E01.0 in this effective period.

Excludes 1

Official

congenital iodine-deficiency syndrome (E00.-)
subclinical iodine-deficiency hypothyroidism (E02)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E01.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E01.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E01.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should confirm diffuse thyroid enlargement attributed to iodine deficiency, with distinction from other causes of goiter (autoimmune thyroiditis, Graves disease).

Thyroid function tests, iodine status assessment if available, thyroid ultrasound findings showing diffuse enlargement without dominant nodules, and any symptoms related to goiter size (dysphagia, dyspnea) should be recorded.

The endemic or iodine-deficiency etiology must be specified.

MEAT Support

HCC Buddy guidance

Documentation should confirm diffuse thyroid enlargement attributed to iodine deficiency, with distinction from other causes of goiter (autoimmune thyroiditis, Graves disease).

The endemic or iodine-deficiency etiology must be specified.

Audit Caution

HCC Buddy guidance

Distinguish iodine-deficiency related goiter from other causes of diffuse thyroid enlargement.

In developed nations with iodine supplementation, endemic goiter is uncommon, and other etiologies should be considered first.

Do not assign this code for multinodular goiter (use E01.1).

Ensure thyroid function status is documented as it affects management.

Common Mistakes

HCC Buddy guidance

E04.0 (Nontoxic diffuse goiter) is the appropriate code when the goiter is not related to iodine deficiency.

E01.1 (Iodine-deficiency related multinodular goiter) is used when the goiter has progressed to multinodular morphology.

E05.00 (Thyrotoxicosis with diffuse goiter) captures a toxic goiter with hyperthyroidism.

E06.3 (Autoimmune thyroiditis) may also cause diffuse goiter but has a different etiology.

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is E01.0 an HCC code?

E01.0 is not in the CMS-HCC V28 or V24 community payment model. E01.0 has a separate mapping under the Part D RxHCC model (HCC 44 (Thyroid Disorders)); the applicable result needs member context.

Code: E01.0
Description: Iodine-deficiency related diffuse (endemic) goiter
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 44, Thyroid Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work E01.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for E01.0

For E01.0 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed E01.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E01.0 is the ICD-10-CM diagnosis code for iodine-deficiency related diffuse (endemic) goiter. An enlarged thyroid gland (goiter) that develops in areas with low iodine in the diet, affecting the entire thyroid uniformly rather than forming nodules. E01.0 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of thyroid gland (e00-e07).

E01.0 has no mapping under the CMS-HCC V28 or V24 community payment models. E01.0 has a separate mapping under the Part D RxHCC model (HCC 44 (Thyroid Disorders)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Document the geographic region or endemic area when possible, as this helps establish the iodine-deficiency etiology.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E01.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the geographic region or endemic area when possible, as this helps establish the iodine-deficiency etiology
•Distinguish from multinodular goiter (E01.1) by confirming the goiter is diffuse rather than nodular

Clinical Significance

Iodine-deficiency related diffuse (endemic) goiter represents thyroid enlargement due to chronic iodine deficiency in geographic regions where iodine intake is insufficient. The thyroid gland enlarges diffusely as a compensatory response to produce adequate thyroid hormone despite limited iodine availability. While patients often maintain euthyroid status initially, progression to hypothyroidism or development of autonomous nodules with thyrotoxicosis can occur over time.

Documentation Requirements

✓Documentation should confirm diffuse thyroid enlargement attributed to iodine deficiency, with distinction from other causes of goiter (autoimmune thyroiditis, Graves disease).
✓Thyroid function tests, iodine status assessment if available, thyroid ultrasound findings showing diffuse enlargement without dominant nodules, and any symptoms related to goiter size (dysphagia, dyspnea) should be recorded.
✓The endemic or iodine-deficiency etiology must be specified.

Commonly Confused Codes

•E04.0 (Nontoxic diffuse goiter) is the appropriate code when the goiter is not related to iodine deficiency.
•E01.1 (Iodine-deficiency related multinodular goiter) is used when the goiter has progressed to multinodular morphology.
•E05.00 (Thyrotoxicosis with diffuse goiter) captures a toxic goiter with hyperthyroidism.
•E06.3 (Autoimmune thyroiditis) may also cause diffuse goiter but has a different etiology.