E01.0
BillableIodine-deficiency related diffuse (endemic) goiter
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E01.0 an HCC code?
No. E01.0 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 E01.0
For E01.0to 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.
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 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). The clinical importance lies in documenting the etiology of thyroid disease for appropriate long-term management rather than risk adjustment.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, 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.