E05.10 ICD-10-CM Code: Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm
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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 guidanceThyrotoxicosis 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
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.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
MappedHCC 44
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
Official- Thyrotoxicosis with toxic uninodular goiter
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E05.10 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E05.10 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E05.10 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E05.10 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E05.10 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for E05.10 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is E05.10 an HCC code?
No. E05.10 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
Work E05.10 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for E05.10
For E05.10to 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 E05.10 during that encounter, not just copy-forwarded from a problem list.
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 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This code does not map to any HCC under V24 or V28, providing no community risk adjustment impact. It maps to RxHCC 44 (Osteoporosis, Vertebral and Pathological Fractures). Accurate coding supports clinical management of this distinct form of hyperthyroidism and prescription drug plan risk adjustment.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, 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
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.