Parathyroid disorders are frequently diagnosed in patients who have not noticed any signs or symptoms of the disease. The disorders are often detected due to atypical results of blood tests performed for other reasons.

Blood tests that show abnormal levels of calcium, parathyroid hormone (PTH), phosphorus and magnesium may indicate a parathyroid disorder. For example, high levels of calcium and PTH and low amounts of phosphorus usually indicate hyperparathyroidism. Conversely, low levels of calcium, PTH and magnesium in the blood indicates hypoparathyroidism.

If a patient’s calcium levels are high, physicians may also perform tests to rule out other causes, such as vitamin D intoxication, sarcoidosis (a disease marked by formation of inflammatory lumps in organs), hyperthyroidism, adrenal failure, prolonged immobilization and certain cancers.

Additional methods may confirm the diagnosis of a parathyroid disorder and the effect the disease has had on the body. These may include:

• Urine tests. Patients may be asked to collect samples of their urine over a 24-hour period. An analysis of these samples may be able to measure the amount of calcium being excreted, as well as provide information about possible kidney damage or the formation of kidney stones. Other tests of kidney function may also be ordered, such as glomerular filtration rate.
  
  
• Imaging tests. A variety of procedures, including ultrasound, may be used to locate and measure the size of the patient’s parathyroid glands, as well as to look for tumors. A sestamibi scan is a nuclear medicine scan that may help to localize a parathyroid tumor. Bone density tests such as a DEXA scan (dual-energy x-ray absorptiometry) can detect the osteoporosis that may result from hyperparathyroidism.
  
  
• Electrocardiogram (EKG or ECG). Hypoparathyroidism may cause abnormal heart rhythms that are detectable with an EKG.