ICD-10-CM Code E21.3

Hyperparathyroidism, unspecified

Version 2021 Billable Code

Valid for Submission

E21.3 is a billable code used to specify a medical diagnosis of hyperparathyroidism, unspecified. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code E21.3 might also be used to specify conditions or terms like brown tumor of hyperparathyroidism, calcifying panniculitis due to hyperparathyroidism, hyperparathyroidism, myopathy in hyperparathyroidism, neonatal hyperparathyroidism, subcutaneous calcification, etc

Short Description:Hyperparathyroidism, unspecified
Long Description:Hyperparathyroidism, unspecified

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code E21.3 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Brown tumor of hyperparathyroidism
  • Calcifying panniculitis due to hyperparathyroidism
  • Hyperparathyroidism
  • Myopathy in hyperparathyroidism
  • Neonatal hyperparathyroidism
  • Subcutaneous calcification

Clinical Information

  • HYPERPARATHYROIDISM-. a condition of abnormally elevated output of parathyroid hormone or pth triggering responses that increase blood calcium. it is characterized by hypercalcemia and bone resorption eventually leading to bone diseases. primary hyperparathyroidism is caused by parathyroid hyperplasia or parathyroid neoplasms. secondary hyperparathyroidism is increased pth secretion in response to hypocalcemia usually caused by chronic kidney diseases.
  • HYPERPARATHYROIDISM SECONDARY-. abnormally elevated parathyroid hormone secretion as a response to hypocalcemia. it is caused by chronic kidney failure or other abnormalities in the controls of bone and mineral metabolism leading to various bone diseases such as renal osteodystrophy.
  • HYPERPARATHYROIDISM PRIMARY-. a condition of abnormally elevated output of parathyroid hormone due to parathyroid hyperplasia or parathyroid neoplasms. it is characterized by the combination of hypercalcemia phosphaturia elevated renal 125 dihydroxyvitamin d3 synthesis and increased bone resorption.

Diagnostic Related Groups

The ICD-10 code E21.3 is grouped in the following groups for version MS-DRG V38.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2020 through 09/30/2021.


Convert E21.3 to ICD-9

  • 252.00 - Hyperparathyroidism NOS

Code Classification

  • Endocrine, nutritional and metabolic diseases (E00–E90)
    • Disorders of other endocrine glands (E20-E35)
      • Hyperparathyroidism and other disorders of parathyroid gland (E21)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients

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.

If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.

If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders, or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

  • Calcium - ionized (Medical Encyclopedia)
  • Calcium - urine (Medical Encyclopedia)
  • Calcium blood test (Medical Encyclopedia)
  • Hypercalcemia - discharge (Medical Encyclopedia)
  • Hyperparathyroidism (Medical Encyclopedia)
  • Hypoparathyroidism (Medical Encyclopedia)
  • Parathyroid adenoma (Medical Encyclopedia)
  • Parathyroid biopsy (Medical Encyclopedia)
  • Parathyroid cancer (Medical Encyclopedia)
  • Parathyroid gland removal (Medical Encyclopedia)
  • Parathyroid hormone (PTH) blood test (Medical Encyclopedia)

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