Coding and coverage · ICD-10-CM

E21 Hyperparathyroidism and other disorders of parathyroid gland

Not billable (header)Chapter 4

Report one of the more specific codes below.

Check coverage with this diagnosis

Codes under this one

  • E21.0 Primary hyperparathyroidism
  • E21.1 Secondary hyperparathyroidism, not elsewhere classified
  • E21.2 Other hyperparathyroidism
  • E21.3 Hyperparathyroidism, unspecified
  • E21.4 Other specified disorders of parathyroid gland
  • E21.5 Disorder of parathyroid gland, unspecified

Instructional notes

Chapter 4

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
  • transitory endocrine and metabolic disorders specific to newborn (P70-P74)
Notes
  • 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.

Section E20-E35

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.

This code

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
  • adult osteomalacia (M83.-)
  • ectopic hyperparathyroidism (E34.2)
  • hungry bone syndrome (E83.81)
  • infantile and juvenile osteomalacia (E55.0)
Excludes2Not included here: the patient may have both; report both when both are present.
  • familial hypocalciuric hypercalcemia (E83.52)

Chapter 4: Endocrine, nutritional and metabolic diseases · E20-E35 Disorders of other endocrine glands (E20-E35)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.