ICD-10-CM 2027
ICD-10 code for Tertiary hyperparathyroidism
From the official ICD-10-CM alphabetic index entry “Hyperparathyroidism › tertiary”. Page updated September 29, 2026.
About coding Tertiary hyperparathyroidism
The ICD-10-CM code for Tertiary hyperparathyroidism is E21.2 (Other hyperparathyroidism).
Within E21, choose E21.2 (Other hyperparathyroidism) only when documentation doesn't support a more specific option: primary hyperparathyroidism (E21.0), secondary hyperparathyroidism, not elsewhere classified (E21.1), hyperparathyroidism, unspecified (E21.3), other specified disorders of parathyroid gland (E21.4) and disorder of parathyroid gland, unspecified (E21.5).
The conditions in its Excludes2 note aren't part of E21.2, but may be coded alongside it if the patient has both: familial hypocalciuric hypercalcemia (E83.52).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Common questions about Tertiary hyperparathyroidism ICD-10 codes
What is the ICD-10 code for Tertiary hyperparathyroidism?
- E21.2 — Other hyperparathyroidism.
Is E21.2 billable?
- Yes. E21.2 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E21.2 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E21.2 as a principal diagnosis.
Is E21.2 a CC or MCC?
- No. E21.2 is neither a CC nor an MCC under MS-DRG v44.0.