PTH may be requested when a blood calcium or phosphate result is abnormal. PTH may be requested when you have hypercalcaemia, which may cause symptoms such as tiredness, sickness, stomach pain, and thirst. PTH may also be requested when you have hypocalcaemia, which may cause symptoms such as muscle cramps and tingling fingers. Your doctor may request a PTH, along with calcium (and other tests) as a way of monitoring changes when you have had treatment for diseases or conditions that affect calcium regulation, such as the removal of a parathyroid tumour, or when you have chronic conditions such as kidney disease.When a person has hyperparathyroidism, the usual treatment is surgery to remove the enlarged gland or glands. Usually in primary hyperparathyroidism, only one abnormal parathyroid gland is present, but in some cases two or more of the glands are abnormal. In secondary hyperparathyroidism, usually all four of the parathyroid glands are affected. During surgery, it is important for the surgeon to make sure that all of the abnormal glands have been removed. If all are abnormal, this usually means removing three glands completely and part of the fourth, leaving behind just enough parathyroid tissue to prevent hypoparathyroidism. One way to be sure that all of the abnormal tissue has been removed is to measure PTH before and after an apparently abnormal gland has been removed. If all the abnormal tissue is gone, PTH levels will fall by over 50% within 10 minutes. To be useful, this requires that the laboratory be able to provide the results quickly (this is often called rapid or intra-operative PTH measurement). This is not available in all UK laboratories.
Parathyroid hormone (PTH) is required for calcium and phosphate balance. It is part of a ‘feedback loop’ that includes calcium, PTH, vitamin D, phosphate and magnesium. Conditions and diseases that disrupt this feedback loop can cause inappropriate elevations or decreases in calcium and PTH and lead to symptoms of hypercalcaemia (raised blood concentrations of calcium) or hypocalcaemia (low blood concentrations of calcium). PTH is…Parathyroid hormone (PTH) is required for calcium and phosphate balance. It is part of a ‘feedback loop’ that includes calcium, PTH, vitamin D, phosphate and magnesium. Conditions and diseases that disrupt this feedback loop can cause inappropriate elevations or decreases in calcium and PTH and lead to symptoms of hypercalcaemia (raised blood concentrations of calcium) or hypocalcaemia (low blood concentrations of calcium). PTH is produced by four parathyroid glands that are located in the neck beside the thyroid gland. Normally, these glands secrete PTH into the bloodstream to regulate blood calcium concentration. Parathyroid hormone works in three ways to control blood calcium levels.. It takes calcium from bone, stimulates the activation of vitamin D in the kidney (which in turn increases the absorption of calcium from the intestines), and suppresses the excretion of calcium in the urine (while encouraging excretion of phosphate). As blood calcium concentrations rise, the concentration of PTH will normally decrease. Parathyroid hormone is composed of 84 amino acids (sometimes called PTH (1-84)). Once it is released from the parathyroid gland into the blood stream, it has a very short life-span and levels fall by half in less than 5 minutes. The fall is caused primarily by the breakdown of PTH to smaller fragments. How is the sample collected for testing? A blood sample is obtained by inserting a needle into a vein in the arm. Is any test preparation needed to ensure the quality of the sample? No test preparation is needed. See MoreSee Less
