E21.1

Billable

Secondary hyperparathyroidism, not elsewhere classified

HCC Category Mapping

V24HCC 23 — Other Significant Endocrine and Metabolic Disorders

0.230

ESRDHCC 23 — Other Significant Endocrine and Metabolic Disorders

0.000

RxHCCHCC 43 — Other Significant Endocrine and Metabolic Disorders

0.000

What This Code Means

Elevated parathyroid hormone levels that develop as a consequence of another disease, most commonly chronic kidney disease, but not specified elsewhere.

Coding Tips

•Always code the underlying condition (such as chronic kidney disease) in addition to this code
•This code is used when secondary hyperparathyroidism is not due to kidney disease or vitamin D deficiency specifically

Clinical Significance

Secondary hyperparathyroidism develops as a compensatory response to conditions causing hypocalcemia or phosphate retention, most commonly chronic kidney disease. The parathyroid glands become overactive to maintain calcium homeostasis, leading to bone disease and vascular calcification over time.

Documentation Requirements

✓Document the underlying cause (chronic kidney disease stage, vitamin D deficiency, malabsorption), parathyroid hormone levels, calcium and phosphorus levels, and treatment approach including phosphate binders or vitamin D analogs.

Excludes 1 — Do NOT code together

secondary hyperparathyroidism of renal origin (N25.81)

Commonly Confused Codes

E21.0 (primary hyperparathyroidism from intrinsic gland disease), N25.81 (secondary hyperparathyroidism of renal origin, which is the preferred code when due to chronic kidney disease), E21.3 (hyperparathyroidism unspecified).

Code Hierarchy

└E21Hyperparathyroidism and other disorders of parathyroid gland └E21.1Secondary hyperparathyroidism, not elsewhere classified

└E21.1Secondary hyperparathyroidism, not elsewhere classified