Its body level is measured by the Intact Parathyroid Hormone (iPTH) test. Calcium, vitamin D, and phosphorus levels in the blood and bones are controlled by iPTH. When calcium levels rise or fall abnormally, it determines the underlying cause. This makes it possible to determine whether other organs, lifestyle choices, or parathyroid dysfunction is to blame. The iPTH test is a fantastic tool for tracking the effectiveness of a parathyroid medication. Kidney disease is the main factor contributing to an increase in PTH Intact levels, whereas iPTH levels below normal can be caused by hypoparathyroidism (low parathyroid hormone levels) or by taking too much calcium or vitamin D.