E01.8
BillableOther iodine-deficiency related thyroid disorders and allied conditions
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E01.8 an HCC code?
No. E01.8 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 E01.8
For E01.8to 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 E01.8 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E01.8 is the ICD-10-CM diagnosis code for other iodine-deficiency related thyroid disorders and allied conditions. Other thyroid problems and related conditions caused by iodine deficiency that don't fit into the standard diffuse or multinodular goiter categories. E01.8 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).
E01.8 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 primary coding value is clinical documentation accuracy and prescription drug plan risk adjustment.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E01.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code for iodine-deficiency related thyroid conditions not classified elsewhere, such as thyroiditis or thyroid dysfunction
- •Document the specific thyroid condition present to support medical necessity
Clinical Significance
Other iodine-deficiency related thyroid disorders and allied conditions captures thyroid conditions caused by iodine deficiency that do not fit the specific goiter codes (E01.0-E01.2). This includes acquired iodine-deficiency hypothyroidism, iodine-deficiency related thyroid dysfunction without goiter, and other iodine-related endocrine conditions. The clinical impact depends on the specific condition but relates to the thyroid's inability to function optimally due to iodine substrate deficiency.
Documentation Requirements
- ✓Documentation must specify the particular iodine-deficiency related thyroid disorder that does not fit the goiter categories.
- ✓The provider should document the clinical manifestation, thyroid function tests, evidence of iodine deficiency, and treatment plan.
- ✓If hypothyroidism is present, the degree and treatment response should be recorded.
- ✓The relationship to iodine deficiency must be explicitly stated.
Commonly Confused Codes
- •E01.0-E01.2 capture iodine-deficiency goiter specifically.
- •E02 (Subclinical iodine-deficiency hypothyroidism) is a more specific code for mild hypothyroidism from iodine deficiency.
- •E03.8 (Other specified hypothyroidism) captures hypothyroidism from non-iodine-deficiency causes.
- •E07.89 (Other specified disorders of thyroid) captures non-iodine-related thyroid disorders.