PTH (parathyroid hormone) is the hormone released by the parathyroid glands; older assays measured total circulating PTH plus inactive fragments. iPTH (intact PTH) specifically measures the full-length, biologically active 1–84 peptide. iPTH assays better reflect true hormone activity and are preferred for diagnosing parathyroid disorders and managing kidney disease, where fragments can accumulate.

An elevated intact PTH means the parathyroid glands are overactive. Causes include primary hyperparathyroidism (autonomous gland disease causing high calcium), secondary causes (low calcium from vitamin D deficiency or chronic kidney disease stimulating PTH), or tertiary hyperparathyroidism after long-standing secondary disease. It warrants checking serum calcium, vitamin D and kidney function and endocrine evaluation.

Intact parathyroid hormone (iPTH) is the full-length biologically active hormone secreted by the parathyroid glands that regulates blood calcium and phosphate levels. iPTH raises serum calcium by stimulating bone resorption, increasing renal calcium reabsorption and activating vitamin D, while reducing renal phosphate reabsorption. Measurement of iPTH helps diagnose primary and secondary hyperparathyroidism, hypoparathyroidism and monitor chronic kidney disease.

The intact parathyroid hormone (iPTH) test measures circulating PTH to assess parathyroid gland function and calcium–phosphate balance. It helps diagnose primary and secondary hyperparathyroidism or hypoparathyroidism, clarifies causes of abnormal blood calcium, and guides or monitors treatment—especially in chronic kidney disease, dialysis patients, and after parathyroid surgery or vitamin D therapy.

iPTH (intact parathyroid hormone) is the laboratory measurement of the whole circulating PTH molecule used in nephrology to assess parathyroid function and mineral metabolism in chronic kidney disease. It helps detect and monitor secondary hyperparathyroidism, reflecting disturbances in calcium, phosphate and active vitamin D; results guide therapies such as phosphate control, vitamin D analogs and calcimimetics to prevent bone and cardiovascular complications.

Parathyroid hormone (PTH) is not a general tumor marker. It’s a physiological hormone measured to diagnose and manage parathyroid disorders—elevated PTH suggests primary hyperparathyroidism, often from a parathyroid adenoma (or rarely carcinoma)—but it isn’t used to screen for most cancers. Some tumors produce PTH-related peptide (PTHrP), causing hypercalcemia, which is distinct from circulating PTH.