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ICD-10 Guide
ICD-10 CodesChapter 4: Endocrine, nutritional and metabolic diseasesE21

E21

Billable

Hyperparathyroidism and other disorders of parathyroid gland

Chapter 4:Endocrine, nutritional and metabolic diseases

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 E21 is a billable code used to indicate a diagnosis of hyperparathyroidism and other disorders of parathyroid gland.

Key Diagnostic Point:

Hyperparathyroidism is a condition characterized by excessive secretion of parathyroid hormone (PTH) from the parathyroid glands, which are small glands located behind the thyroid gland. This condition leads to elevated levels of calcium in the blood (hypercalcemia), which can result in various symptoms including kidney stones, osteoporosis, and abdominal pain. There are three main types of hyperparathyroidism: primary, secondary, and tertiary. Primary hyperparathyroidism is often caused by a benign tumor on a parathyroid gland (adenoma), while secondary hyperparathyroidism is typically a response to low calcium levels due to chronic kidney disease or vitamin D deficiency. Tertiary hyperparathyroidism occurs when the parathyroid glands become overactive after prolonged secondary hyperparathyroidism. Other disorders of the parathyroid gland may include hypoparathyroidism, which is characterized by insufficient PTH production, leading to low calcium levels and associated symptoms such as muscle cramps and seizures. Accurate diagnosis and management of these conditions require a thorough understanding of the endocrine system and its hormonal interactions.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between primary, secondary, and tertiary hyperparathyroidism
  • Understanding the relationship between calcium levels and parathyroid hormone
  • Identifying coexisting endocrine disorders
  • Interpreting laboratory results accurately

Audit Risk Factors

  • Inadequate documentation of laboratory results
  • Failure to specify the type of hyperparathyroidism
  • Incorrect coding of related conditions such as osteoporosis or kidney stones
  • Lack of clarity in the treatment plan or surgical interventions

Specialty Focus

Medical Specialties

Endocrinology

Documentation Requirements

Detailed lab results, imaging studies, and treatment plans must be documented.

Common Clinical Scenarios

Diagnosis and management of hyperparathyroidism, monitoring of calcium levels, and treatment of related complications.

Billing Considerations

Endocrinologists must ensure that all relevant hormonal assays are documented to support the diagnosis.

Nephrology

Documentation Requirements

Documentation of renal function tests and calcium-phosphate metabolism is essential.

Common Clinical Scenarios

Management of secondary hyperparathyroidism in patients with chronic kidney disease.

Billing Considerations

Nephrologists should document the relationship between kidney function and parathyroid hormone levels.

Coding Guidelines

Inclusion Criteria

Use E21 When
  • Follow the official ICD
  • CM coding guidelines for endocrine disorders
  • Ensure accurate documentation of the type of hyperparathyroidism and any associated conditions
  • Include relevant laboratory results to support the diagnosis

Exclusion Criteria

Do NOT use E21 When
No specific exclusions found.

Related CPT Codes

CPT 80048CPT Code

Comprehensive metabolic panel

Clinical Scenario

Used to monitor calcium and electrolyte levels in patients with hyperparathyroidism.

Documentation Requirements

Document all lab results and clinical findings.

Specialty Considerations

Endocrinologists should ensure that all relevant tests are ordered and results are interpreted.

CPT 60500CPT Code

Parathyroidectomy

Clinical Scenario

Surgical intervention for primary hyperparathyroidism.

Documentation Requirements

Operative reports must detail the procedure and findings.

Specialty Considerations

Surgeons must document indications for surgery and any complications.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of hyperparathyroidism, enabling better tracking of patient outcomes and treatment efficacy. It has also improved the granularity of data for research and epidemiological studies.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of hyperparathyroidism, enabling better tracking of patient outcomes and treatment efficacy. It has also improved the granularity of data for research and epidemiological studies.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of hyperparathyroidism, enabling better tracking of patient outcomes and treatment efficacy. It has also improved the granularity of data for research and epidemiological studies.

Resources

Clinical References

  • •
    American Association of Clinical Endocrinologists
  • •
    Endocrine Society Clinical Practice Guidelines

Coding & Billing References

  • •
    American Association of Clinical Endocrinologists
  • •
    Endocrine Society Clinical Practice Guidelines

Frequently Asked Questions

What is the difference between primary and secondary hyperparathyroidism?

Primary hyperparathyroidism is caused by an overproduction of parathyroid hormone due to an adenoma or hyperplasia, while secondary hyperparathyroidism is a compensatory response to low calcium levels, often due to chronic kidney disease or vitamin D deficiency.

How do I document a diagnosis of hyperparathyroidism?

Document the patient's symptoms, laboratory results (including calcium and PTH levels), and any imaging studies performed. Specify the type of hyperparathyroidism to ensure accurate coding.