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ICD-10-CM E01.8: Other iodine-deficiency related thyroid disorders and allied conditions

E01.8 is the billable ICD-10-CM code for other iodine-deficiency related thyroid disorders and allied conditions, in category E01 (Iodine-deficiency related thyroid disorders and allied conditions) of the Disorders of thyroid gland section. As a principal diagnosis it groups to MS-DRG 643 Endocrine Disorders with MCC, MS-DRG 644 Endocrine Disorders with CC, MS-DRG 645 Endocrine Disorders without CC/MCC (MDC 10 MDC 10: Endocrine, Nutritional and Metabolic Diseases and Disorders). 2 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
E01.8
billable FY2027 ICD-10-CM code
Category
E01 Iodine-deficiency related thyroid disorders and allied conditions
Chapter
4: Endocrine, nutritional and metabolic diseases (E00-E89)
CC/MCC (MS-DRG v44)
Neither
CMS-HCC V28
Not mapped
POA reporting
Required

Tabular list notes for E01.8

The tabular list has no notes on E01.8 itself; the notes below apply from its parent headings.

Inherited from E01 (Iodine-deficiency related thyroid disorders and allied conditions)

Excludes1 (never coded together)
  • congenital iodine-deficiency syndrome (E00.-)
  • subclinical iodine-deficiency hypothyroidism (E02)

MS-DRG grouping when E01.8 is the principal diagnosis

MS-DRG v44 groups for E01.8 as principal diagnosis
MDCMS-DRGs
10 MDC 10: Endocrine, Nutritional and Metabolic Diseases and Disorders643644645

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for E01.8 shows the full grouping logic.

CC/MCC status and inpatient edits

E01.8 is neither a CC nor an MCC under MS-DRG v44, so as a secondary diagnosis it does not raise the MS-DRG severity level. Check E01.8 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.

CMS-HCC V28 risk adjustment

E01.8 does not map to a payment HCC in the PY2027 CMS-HCC V28 model, so on its own it does not change a Medicare Advantage risk score.

LCD billing and coding articles that list E01.8

2 current Medicare billing and coding articles list E01.8 among the diagnoses that support medical necessity for the services they cover.

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Frequently asked questions

What does ICD-10-CM E01.8 mean?

E01.8 means other iodine-deficiency related thyroid disorders and allied conditions. It is one of 4 billable codes under E01, iodine-deficiency related thyroid disorders and allied conditions.

What can't be coded with E01.8?

Excludes1 at E01: congenital iodine-deficiency syndrome (E00.-); subclinical iodine-deficiency hypothyroidism (E02). These are never reported together with E01.8.

Which MS-DRG does E01.8 group to?

As the principal diagnosis, E01.8 groups to MS-DRG 643 Endocrine Disorders with MCC, MS-DRG 644 Endocrine Disorders with CC, MS-DRG 645 Endocrine Disorders without CC/MCC (MDC 10 MDC 10: Endocrine, Nutritional and Metabolic Diseases and Disorders) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.