E01.1
BillableIodine-deficiency related multinodular (endemic) goiter
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E01.1 an HCC code?
No. E01.1 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.
MEAT Criteria for E01.1
For E01.1to 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 E01.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E01.1 is the ICD-10-CM diagnosis code for iodine-deficiency related multinodular (endemic) goiter. An enlarged thyroid gland with multiple nodules that develops in areas with low iodine in the diet, where the thyroid develops lumps rather than enlarging uniformly. E01.1 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).
E01.1 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 progressive thyroid condition and prescription drug risk adjustment.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E01.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm the presence of multiple nodules through imaging or clinical documentation to differentiate from diffuse goiter
- •Document any functional status of nodules (toxic vs. non-toxic) if available
Clinical Significance
Iodine-deficiency related multinodular (endemic) goiter represents the progression of chronic iodine deficiency to a thyroid gland with multiple autonomous nodules. This evolution from diffuse to nodular goiter typically occurs over years and carries a risk of toxic multinodular goiter with autonomous thyroid hormone production. Multinodular goiters can also cause compressive symptoms and harbor occult thyroid carcinoma requiring ongoing surveillance.
Documentation Requirements
- ✓Documentation should confirm multinodular thyroid enlargement attributed to iodine deficiency, with imaging (thyroid ultrasound) demonstrating multiple nodules.
- ✓Thyroid function tests, assessment for compressive symptoms, and evaluation for suspicious nodules requiring fine-needle aspiration biopsy should be documented.
- ✓The iodine-deficiency etiology must be distinguished from other causes of multinodular goiter.
Commonly Confused Codes
- •E04.2 (Nontoxic multinodular goiter) is used when the multinodular goiter is not related to iodine deficiency.
- •E01.0 (Iodine-deficiency related diffuse goiter) is used for diffuse enlargement without nodules.
- •E05.20 (Thyrotoxicosis with toxic multinodular goiter) captures multinodular goiter with hyperthyroidism.
- •E01.2 (Iodine-deficiency related goiter, unspecified) is less specific.