PTHspiegels

PTHspiegels refer to the concentration of parathyroid hormone (PTH) in the blood. PTH is a peptide hormone produced by the parathyroid glands and is a central regulator of calcium and phosphate homeostasis. It raises serum calcium by increasing bone resorption, enhancing renal calcium reabsorption, and stimulating the production of active vitamin D (calcitriol), which in turn increases intestinal calcium absorption. At the same time, PTH lowers renal phosphate reabsorption, helping to balance mineral levels.

PTH is usually measured as intact PTH (iPTH) using immunoassays. Results are reported in picograms per milliliter (pg/mL) or in picomoles per liter (pmol/L), with typical reference ranges around 10–65 pg/mL (roughly 1.1–6.8 pmol/L) in individuals with normal kidney function. Reference ranges vary by assay and laboratory. PTH results can be influenced by sample handling and timing, as well as by circadian and meal-related variations; sample collection is often done with care to preserve peptide integrity and may require measuring alongside calcium levels for interpretation.

Clinical interpretation centers on calcium status. In hypercalcemia, PTH is usually suppressed; a high PTH in the setting of hypercalcemia suggests primary hyperparathyroidism or, less commonly, familial hypocalciuric hypercalcemia. In hypocalcemia or vitamin D deficiency, PTH tends to be elevated (secondary hyperparathyroidism). Chronic kidney disease commonly causes secondary hyperparathyroidism due to phosphate retention and reduced calcitriol production. Low PTH with hypercalcemia may indicate PTH-independent causes such as malignancy or vitamin D intoxication.

PTHspiegels are used to evaluate disorders of mineral metabolism, guide assessment of hyper- or hypocalcemia, and monitor conditions such as chronic kidney disease–mineral and bone disorder and post-parathyroidectomy status.