Hyperparathyroidism ICD-10 Code: E21.3
Last updated: January 4, 2026
Hyperparathyroidism is coded based on type: primary, secondary, or tertiary.
Hyperparathyroidism Code Selection
| Code | Description | Cause |
|---|---|---|
| E21.0 | Primary hyperparathyroidism | Parathyroid adenoma, hyperplasia |
| E21.1 | Secondary hyperparathyroidism, NEC | Chronic kidney disease |
| E21.2 | Other hyperparathyroidism | Tertiary HPT |
| E21.3 | Hyperparathyroidism, unspecified | Type not documented |
Secondary HPT Exclusions
E21.1 excludes:
- Secondary hyperparathyroidism of renal origin -> N25.81
| CKD with Secondary HPT | Code |
|---|---|
| CKD stage 3-5 with 2 deg HPT | N18.x + N25.81 |
| ESRD on dialysis with 2 deg HPT | N18.6 + N25.81 |
| Non-renal secondary HPT | E21.1 |
Associated Conditions
| Condition | Code |
|---|---|
| Hypercalcemia | E83.52 |
| Hypophosphatemia | E83.39 |
| Kidney stones | N20.x |
| Osteoporosis | M81.0/M80.x |
| Parathyroid adenoma | D35.1 |
| Parathyroid carcinoma | C75.0 |
Coding Tips
- Query type: Primary vs secondary significantly affects treatment
- Renal secondary HPT: Use N25.81, not E21.1
- Hypercalcemia: Code E83.52 as manifestation
- Post-parathyroidectomy: Use E89.2 for postprocedural hypoparathyroidism
Primary vs Secondary vs Tertiary
| Type | PTH | Calcium | Cause |
|---|---|---|---|
| Primary | High | High | Adenoma, hyperplasia |
| Secondary | High | Low/Normal | CKD, vitamin D deficiency |
| Tertiary | High | High | Long-standing secondary |
Related Codes
| Code | Description |
|---|---|
| E20.0 | Idiopathic hypoparathyroidism |
| E89.2 | Postprocedural hypoparathyroidism |
| N25.81 | Secondary hyperparathyroidism of renal origin |
| D35.1 | Benign neoplasm of parathyroid gland |
Frequently Asked Questions
What is the ICD-10 code for hyperparathyroidism?
E21.0 for primary hyperparathyroidism, E21.1 for non-renal secondary, N25.81 for renal secondary, or E21.3 for unspecified.
How do I code secondary hyperparathyroidism with CKD?
Use the CKD code (N18.x) plus N25.81 (Secondary hyperparathyroidism of renal origin). Do NOT use E21.1 for renal secondary HPT.
What's the difference between primary and secondary hyperparathyroidism?
Primary (E21.0) is autonomous PTH overproduction (adenoma). Secondary (E21.1/N25.81) is reactive to low calcium or CKD. Primary causes hypercalcemia; secondary often doesn't.
Related Resources
Last updated: January 2026. Code data reflects ICD-10-CM 2026 version. This guide is for educational purposes only. Always verify codes against current official guidelines.