Normal blood calcium levels are important for the proper functioning of blood vessels, muscles, and nerve conduction systems. If you have symptoms of hypocalcemia, your doctor may order a blood test to measure the parathyroid hormone (PTH) in your blood to determine if there is a problem with this organ.

Parathyroid hormone (PTH) is a vital hormone of the body, playing a role in regulating the concentration of Ca2+ ions and phosphate ions (PO43-) in the plasma. Under the effect of the hormone, the concentration of calcium ions in the plasma increases but conversely the concentration of phosphate ions decreases.