E05.01 ICD-10-CM Code: Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm
E05.01 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC coding software
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FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of thyroid gland (E00-E07)
E05.01
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceThyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm
A life-threatening emergency where excess thyroid hormone causes thyroid storm, with severe fever, extreme tachycardia, confusion, and potential organ failure.
Buddy Insight
Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm is an acute, life-threatening exacerbation of Graves disease characterized by extreme hyperthyroid manifestations including high fever (greater than 104 degrees Fahrenheit), severe tachycardia or atrial fibrillation, altered mental status, gastrointestinal dysfunction, and cardiovascular collapse.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
MappedHCC 44
RAF 0.070
Code Book Path
Inclusion Terms
Official- Exophthalmic or toxic goiter NOS
- Graves' disease
- Toxic diffuse goiter
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E05.01 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E05.01 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E05.01 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E05.01 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E05.01 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for E05.01 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 E05.01 an HCC code?
E05.01 is not in the CMS-HCC V28 or V24 community payment model, but it does map to Thyroid and Parathyroid Disorders under the Part D RxHCC model.
- Code
- E05.01
- Description
- Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so 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 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 E05.01 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for E05.01
For E05.01 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 E05.01 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
E05.01 is the ICD-10-CM diagnosis code for thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm. A life-threatening emergency where excess thyroid hormone causes thyroid storm, with severe fever, extreme tachycardia, confusion, and potential organ failure. E05.01 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).
E05.01 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 a CMS-HCC V28 payment category. Capture depends on documentation that supports the diagnosis; verify the HCC assignment against the current CMS mapping for the applicable payment year. Coders reviewing E05.01 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC, capturing the correct specificity is the highest-impact RAF improvement available within accurate coding.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E05.01 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a medical emergency; ensure appropriate critical care codes and comorbidities are documented
- •Document precipitating factors (infection, medication non-compliance, surgery) and treatment provided (antithyroid drugs, beta-blockers, iodine)
Clinical Significance
Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm is an acute, life-threatening exacerbation of Graves disease characterized by extreme hyperthyroid manifestations including high fever (greater than 104 degrees Fahrenheit), severe tachycardia or atrial fibrillation, altered mental status, gastrointestinal dysfunction, and cardiovascular collapse. Mortality rates range from 10-30% even with aggressive treatment. Precipitants include infection, surgery, radioactive iodine therapy, and medication non-adherence.
Documentation Requirements
- ✓Documentation must clearly establish thyroid storm using clinical scoring systems (Burch-Wartofsky Point Scale score greater than 45).
- ✓Clinical findings including temperature, heart rate, central nervous system manifestations, gastrointestinal dysfunction, and precipitating event should be recorded.
- ✓Thyroid function tests, treatment administered (thionamides, iodine, beta-blockers, corticosteroids, cooling measures), and intensive care management should be documented.
Commonly Confused Codes
- •E05.00 (Thyrotoxicosis with diffuse goiter WITHOUT thyrotoxic crisis) captures stable Graves disease hyperthyroidism.
- •E05.91 (Thyrotoxicosis, unspecified with thyrotoxic crisis or storm) is less specific regarding the type of thyrotoxicosis.
- •E05.11 (Thyrotoxicosis with toxic single thyroid nodule with crisis) captures storm from nodular disease.
- •R50.9 (Fever, unspecified) may be assigned concurrently but does not replace the thyroid storm code.