2027 ICD-10-CM Diagnosis Code E21Hyperparathyroidism and other disorders of parathyroid gland

ICD-10-CM Codes›E00–E89›E20-E35›E21

ICD-10-CM E21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

E21 is a non-billable ICD-10-CM category code for hyperparathyroidism and other disorders of parathyroid gland, so it cannot be submitted on claims. Use a more specific code from this category instead, such as E21.0, E21.1, E21.2, and E21.3.

Code Identity

ICD-10-CM Code
E21
Billable Status
No — Non-Billable Category
Code Describes
Hyperparathyroidism and other disorders of parathyroid gland
Short Description
Hyperparathyroidism and other disorders of parathyroid gland
Same as the full description in the CMS dataset.
Chapter
E20-E35
Disorders of other endocrine glands

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE20-E35Disorders of other endocrine glands
CategoryE21Hyperparathyroidism and other disorders of parathyroid gland
This CodeE21Hyperparathyroidism and other disorders of parathyroid gland

Specific Coding for Hyperparathyroidism and other disorders of parathyroid glandOverview

Non-specific codes like E21 require more characters. Use one of these billable codes instead:

  • Use E21.0 for Primary hyperparathyroidism

  • Use E21.1 for Secondary hyperparathyroidism, not elsewhere classified

  • Use E21.2 for Other hyperparathyroidism

  • Use E21.3 for Hyperparathyroidism, unspecified

  • Use E21.4 for Other specified disorders of parathyroid gland

  • Use E21.5 for Disorder of parathyroid gland, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to E21: its own notes plus those printed at block E20-E35 and Chapter 4. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

On E21 itself
  • adult osteomalacia (M83.-)
  • ectopic hyperparathyroidism (E34.2)
  • hungry bone syndrome (E83.81)
  • infantile and juvenile osteomalacia (E55.0)
From Block E20-E35 Disorders of other endocrine glands applies to 99 codes
From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • transitory endocrine and metabolic disorders specific to newborn (P70-P74)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

  • familial hypocalciuric hypercalcemia (E83.52)

Notes

General instructions on how these codes are used.

From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name E21, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming E21: they are not reported together with it, unless the two conditions are unrelated.

  • E83 Disorders of mineral metabolism
    parathyroid disorders (E20-E21) names E20-E21, which includes this code

Code First 2

These codes say to code first a condition named in the note, and E21 is one of the conditions named.

  • M14.8 Arthropathies in other specified diseases classified elsewhere
    hyperparathyroidism (E21.-)
  • G63 Polyneuropathy in diseases classified elsewhere
    endocrine disease, except diabetes (E00-E07, E15-E16, E20-E34) names E20-E34, which includes this code

Notes 1

These notes mention E21.

  • Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases
    All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere. names E16-E31, which includes this code

Patient EducationClinical

Parathyroid Disorders

Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About E21Overview

What is the ICD-10 code for hyperparathyroidism and other disorders of parathyroid gland?

E21 is the ICD-10-CM category for hyperparathyroidism and other disorders of parathyroid gland, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is E21 (Hyperparathyroidism and other disorders of parathyroid gland) a billable code?

No. This is a category header that groups the codes for hyperparathyroidism and other disorders of parathyroid gland, and headers cannot be submitted on claims. Claims for hyperparathyroidism and other disorders of parathyroid gland need a more specific code from this category, such as E21.0, E21.1, and E21.2.

Can E21 be reported with a code from M83?

Not as a rule. The Excludes1 note on E21 lists "adult osteomalacia (M83.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).