What is ICD-10 code E05.10?

E05.10 is the ICD-10-CM diagnosis code for Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm. Overactive thyroid caused by a single nodule producing excess thyroid hormone, without a thyroid storm (life-threatening condition). E05.10 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E05.10 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. E05.10 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. E05.10 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 E05.10 map to under V28?

E05.10 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for E05.10?

E05.10 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for E05.10?

E05.10 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports E05.10?

Verify documentation specifies a single nodule; if multiple nodules are present, use E05.20 instead Confirm absence of thyrotoxic crisis or storm; if present, use E05.11 E05.10 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 E05.10: Thyrotoxicosis with toxic single

E05.10 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupE05.10

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E05.10

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

Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

Overactive thyroid caused by a single nodule producing excess thyroid hormone, without a thyroid storm (life-threatening condition).

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

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

E05Thyrotoxicosis [hyperthyroidism]E05.1Thyrotoxicosis with toxic single thyroid nodule E05.10Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

Inclusion Terms

Official

Thyrotoxicosis with toxic uninodular goiterInherited from E05.1

Excludes 2

Official

No Excludes 2 notes are included in this display for E05.10. Check the code and parent instructions in the Code Book.

Related Codes

Official

E05.11Thyrotoxicosis with toxic single thyroid nodule with thyrotoxic crisis or storm

Includes

Official

No Includes notes are included in this display for E05.10. Check the code and parent instructions in the Code Book.

Excludes 1

Official

transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E05
chronic thyroiditis with transient thyrotoxicosis (E06.2)Inherited from E00-E89, E05
neonatal thyrotoxicosis (P72.1)Inherited from E00-E89, E05

Code First

Official

No Code First sequencing instructions are included in this display for E05.10. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E05.10. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E05.10. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should confirm a single hyperfunctioning thyroid nodule with thyrotoxicosis.

Thyroid function tests (suppressed thyroid-stimulating hormone, elevated free thyroxine), radioactive iodine uptake scan showing focal uptake in the nodule with suppression of surrounding tissue, and clinical symptoms should be documented.

Treatment plan (radioactive iodine, surgery, or antithyroid medications) and response should be recorded.

MEAT Support

HCC Buddy guidance

Documentation should confirm a single hyperfunctioning thyroid nodule with thyrotoxicosis.

Treatment plan (radioactive iodine, surgery, or antithyroid medications) and response should be recorded.

Audit Caution

HCC Buddy guidance

Ensure the nodule is truly toxic (hyperfunctioning) by documenting suppressed thyroid-stimulating hormone and focal uptake on thyroid scan. Do not assign for a nontoxic (cold or warm) nodule without thyrotoxicosis. Confirm that only a single nodule is present; multiple toxic nodules require E05.

If the patient develops thyroid storm, transition to E05.

After definitive treatment resulting in hypothyroidism, transition to the appropriate hypothyroidism code.

Common Mistakes

HCC Buddy guidance

E04.1 (Nontoxic single thyroid nodule) captures a nodule without hyperthyroidism.

E05.11 (Thyrotoxicosis with toxic single thyroid nodule WITH crisis) captures the crisis form.

E05.00 (Thyrotoxicosis with diffuse goiter) captures Graves disease, which has a different mechanism.

E05.20 (Thyrotoxicosis with toxic multinodular goiter) captures multiple hyperfunctioning nodules.

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 E05.10 an HCC code?

E05.10 is not in the CMS-HCC V28 or V24 community payment model. E05.10 has a separate mapping under the Part D RxHCC model (HCC 44 (Thyroid Disorders)); the applicable result needs member context.

Code: E05.10
Description: Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm
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 E05.10 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E05.10

For E05.10, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

E05.10 is the ICD-10-CM diagnosis code for thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm. Overactive thyroid caused by a single nodule producing excess thyroid hormone, without a thyroid storm (life-threatening condition). E05.10 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).

E05.10 has no mapping under the CMS-HCC V28 or V24 community payment models. E05.10 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.

Verify documentation specifies a single nodule; if multiple nodules are present, use E05.20 instead.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E05.10 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify documentation specifies a single nodule; if multiple nodules are present, use E05.20 instead
•Confirm absence of thyrotoxic crisis or storm; if present, use E05.11

Clinical Significance

Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis, also known as Plummer disease or toxic adenoma, occurs when a single autonomously functioning thyroid nodule produces excess thyroid hormone independent of thyroid-stimulating hormone regulation. Unlike Graves disease, this condition lacks autoimmune features such as ophthalmopathy and typically presents in older patients. The autonomous nodule suppresses the remainder of the thyroid gland.

Documentation Requirements

✓Documentation should confirm a single hyperfunctioning thyroid nodule with thyrotoxicosis.
✓Thyroid function tests (suppressed thyroid-stimulating hormone, elevated free thyroxine), radioactive iodine uptake scan showing focal uptake in the nodule with suppression of surrounding tissue, and clinical symptoms should be documented.
✓Treatment plan (radioactive iodine, surgery, or antithyroid medications) and response should be recorded.

Commonly Confused Codes

•E04.1 (Nontoxic single thyroid nodule) captures a nodule without hyperthyroidism.
•E05.11 (Thyrotoxicosis with toxic single thyroid nodule WITH crisis) captures the crisis form.
•E05.00 (Thyrotoxicosis with diffuse goiter) captures Graves disease, which has a different mechanism.
•E05.20 (Thyrotoxicosis with toxic multinodular goiter) captures multiple hyperfunctioning nodules.

Child Codes

E05.10Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

E05.11Thyrotoxicosis with toxic single thyroid nodule with thyrotoxic crisis or storm

Code Hierarchy

└E05Thyrotoxicosis [hyperthyroidism]└E05.1Thyrotoxicosis with toxic single thyroid nodule └E05.10Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

└E05.10Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

E05.10 ICD-10-CM Code: Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm

HCC Buddy Code Card

E05.10

Is E05.10 an HCC code?

HCC Category Mapping

MEAT review for E05.10

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

Work E05.10 in HCC Buddy