On routine life insurance screening, an asymptomatic 45-year-old male is found to have a serum calcium level of 12.5 mg/dL. Serum is obtained for immunoreactive parathyroid hormone level and this is 400 mEq/mL (normal range < 64mEq/mL). These findings are most consistent with a diagnosis of which of the following?
A.	Primary hyperparathyroidism
B.	Secondary hyperparathyroidism
C.	Tertiary hyperparathyroidism
D.	Ectopic hyperparathyroidism
Answer:A
On routine life insurance screening, an asymptomatic 45-year-old male is found to have a serum calcium level of 12.5 mg/dL. Serum is obtained for immunoreactive parathyroid hormone level and this is 400 mEq/mL (normal range < 64mEq/mL). These findings are most consistent with a diagnosis of which of the following?
A.	Primary hyperparathyroidism B.	Secondary hyperparathyroidism C.	Tertiary hyperparathyroidism D.	Ectopic hyperparathyroidism