Understanding Primary Hyperparathyroidism: A Simple Guide What Is Primary Hyperparathyroidism? Primary hyperparathyroidism is a condition where the parathyroid glands produce too much parathyroid hormone (PTH), leading to high calcium levels in the blood. It’s more common than many people realize, affecting about 20 out of every 100,000 people. It occurs … More Primary Hyperparathyroidism