PTH
Parathyroid hormone (PTH) is produced by the four parathyroid glands and is the primary regulator of calcium homeostasis. When blood calcium drops, PTH rises to increase calcium by stimulating bone resorption, kidney calcium reabsorption, and vitamin D activation (which increases intestinal calcium absorption).
Why it matters: High PTH (hyperparathyroidism) causes bone loss, kidney stones, fatigue, and cognitive impairment. The most common cause is a benign parathyroid adenoma (primary hyperparathyroidism). Secondary hyperparathyroidism occurs when vitamin D deficiency or kidney disease chronically lowers calcium, driving PTH compensatory elevation.
May increase with:
May decrease with:
What is PTH?
Parathyroid hormone (PTH) is produced by the four parathyroid glands and is the primary regulator of calcium homeostasis. When blood calcium drops, PTH rises to increase calcium by stimulating bone resorption, kidney calcium reabsorption, and vitamin D activation (which increases intestinal calcium absorption).
What might a high or low PTH mean?
High PTH (hyperparathyroidism) causes bone loss, kidney stones, fatigue, and cognitive impairment. The most common cause is a benign parathyroid adenoma (primary hyperparathyroidism). Secondary hyperparathyroidism occurs when vitamin D deficiency or kidney disease chronically lowers calcium, driving PTH compensatory elevation.
What is the typical reference range for PTH?
The general-population reference range shown here is 1.6 – 6.9 pmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.
What can affect PTH?
It may be higher with: Vitamin D deficiency (secondary hyperparathyroidism — very common), Chronic kidney disease (phosphorus retention), Primary hyperparathyroidism (parathyroid adenoma), Low calcium intake, Magnesium deficiency (severe), Lithium therapy. It may be lower with: Vitamin D supplementation (corrects secondary hyperPTH), Hypercalcemia (any cause — feedback suppression), Hypoparathyroidism (post-surgical, autoimmune), Magnesium deficiency (severe — paradoxically suppresses PTH), Cinacalcet (calcimimetic medication).