Parathyroid hormone (PTH) is a substance produced by four tiny glands in the front of the neck called the parathyroid glands. PTH helps to control blood levels of calcium.

When kidneys fail blood calcium levels can become low. The body compensates by producing more PTH. Sometimes the body over-reacts and produces too much PTH. This causes calcium levels to rise too high. Raised PTH levels are common in patients with kidney failure and this extra PTH aggravates renal bone disease.

PTH can be measured by a blood test