E21Header code — not billable

Hyperparathyroidism and other disorders of parathyroid gland

Chapter
4. Endocrine, nutritional and metabolic diseases
Category
E21
Effective date
October 1, 2026

Related codes in category E21

E21.0Primary hyperparathyroidismYesE21.1Secondary hyperparathyroidism, not elsewhere classifiedYesE21.2Other hyperparathyroidismYesE21.3Hyperparathyroidism, unspecifiedYesE21.4Other specified disorders of parathyroid glandYesE21.5Disorder of parathyroid gland, unspecifiedYes

Frequently asked questions

What is ICD-10 code E21?

E21 is an ICD-10-CM diagnosis code for Hyperparathyroidism and other disorders of parathyroid gland.

Is E21 a billable code?

No. E21 is a category/header code, not billable on its own — use one of its more specific child codes instead.

What ICD-10-CM chapter is E21 in?

E21 falls under Chapter 4: Endocrine, nutritional and metabolic diseases.

When did E21 become effective?

E21 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to E21?

E21 belongs to category E21, which includes 6 other codes — see the related codes list on this page.

ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.