2021 ICD-10-CM Diagnosis Code E21

Hyperparathyroidism and other disorders of parathyroid gland

    2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
  • E21 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2021 edition of ICD-10-CM E21 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of E21 - other international versions of ICD-10 E21 may differ.
Type 1 Excludes
Type 1 Excludes Help
A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as E21. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • adult osteomalacia (
    ICD-10-CM Diagnosis Code M83
    • M83 Adult osteomalacia
      • M83.0 Puerperal osteomalacia
      • M83.1 Senile osteomalacia
      • M83.2 Adult osteomalacia due to malabsorption
      • M83.3 Adult osteomalacia due to malnutrition
      • M83.4 Aluminum bone disease
      • M83.5 Other drug-induced osteomalacia in adults
      • M83.8 Other adult osteomalacia
      • M83.9 Adult osteomalacia, unspecified
  • ectopic hyperparathyroidism (
    ICD-10-CM Diagnosis Code E34.2

    Ectopic hormone secretion, not elsewhere classified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Type 1 Excludes
    • ectopic ACTH syndrome (E24.3)
  • familial hypocalciuric hypercalcemia (
    ICD-10-CM Diagnosis Code E83.52


      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Familial hypocalciuric hypercalcemia
  • hungry bone syndrome (
    ICD-10-CM Diagnosis Code E83.81

    Hungry bone syndrome

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
  • infantile and juvenile osteomalacia (
    ICD-10-CM Diagnosis Code E55.0

    Rickets, active

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Infantile osteomalacia
    • Juvenile osteomalacia
    Type 1 Excludes
    • celiac rickets (K90.0)
    • Crohn's rickets (K50.-)
    • hereditary vitamin D-dependent rickets (E83.32)
    • inactive rickets (E64.3)
    • renal rickets (N25.0)
    • sequelae of rickets (E64.3)
    • vitamin D-resistant rickets (E83.31)
The following code(s) above E21 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to E21:
  • E00-E89
    2021 ICD-10-CM Range 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.
    Type 1 Excludes
    • transitory endocrine and metabolic disorders specific to newborn (P70-P74)
    Endocrine, nutritional and metabolic diseases
  • E20-E35
    2021 ICD-10-CM Range E20-E35

    Disorders of other endocrine glands

    Type 1 Excludes
    Disorders of other endocrine glands
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
Code annotations containing back-references to E21:
  • Code First: M14.8
    ICD-10-CM Diagnosis Code M14.8

    Arthropathies in other specified diseases classified elsewhere

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Code First
    • underlying disease, such as:
    • amyloidosis (E85.-)
    • erythema multiforme (L51.-)
    • erythema nodosum (L52)
    • hemochromatosis (E83.11-)
    • hyperparathyroidism (E21.-)
    • hypothyroidism (E00-E03)
    • sickle-cell disorders (D57.-)
    • thyrotoxicosis [hyperthyroidism] (E05.-)
    • Whipple's disease (K90.81)
ICD-10-CM Codes Adjacent To E21
E16.2 Hypoglycemia, unspecified
E16.3 Increased secretion of glucagon
E16.4 Increased secretion of gastrin
E16.8 Other specified disorders of pancreatic internal secretion
E16.9 Disorder of pancreatic internal secretion, unspecified
E20 Hypoparathyroidism
E20.0 Idiopathic hypoparathyroidism
E20.1 Pseudohypoparathyroidism
E20.8 Other hypoparathyroidism
E20.9 Hypoparathyroidism, unspecified
E21 Hyperparathyroidism and other disorders of parathyroid gland
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
E22 Hyperfunction of pituitary gland
E22.0 Acromegaly and pituitary gigantism
E22.1 Hyperprolactinemia
E22.2 Syndrome of inappropriate secretion of antidiuretic hormone

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.