Final answer:
Parathyroid hormone (PTH) should be checked for normal levels in a person with recurring kidney stones.
Step-by-step explanation:
The hormone that should be checked for normal levels in a person with recurring kidney stones is parathyroid hormone (PTH). Parathyroid hormone is produced by the parathyroid glands and it plays a key role in regulating the balance of mineral ions in the body, including calcium and phosphorus. By stimulating the kidneys to excrete less calcium and more phosphorus in the urine, PTH helps increase the blood calcium levels and reduce the risk of kidney stone formation.