Blood tests

If the result of a blood test indicates you have elevated calcium in your blood, your doctor will likely repeat the test to confirm the results after you have not eaten for a period of time (fasted).

A number of conditions can raise calcium levels, but your doctor can make a diagnosis of hyperparathyroidism if blood tests show you also have elevated parathyroid hormone.

Additional diagnostic tests

After making a diagnosis of hyperparathyroidism, your doctor will likely order additional tests to rule out possible secondary causes, to identify possible complications and to judge the severity of the condition. These tests include:

• Bone mineral density test (bone densitometry). The most common test to measure bone mineral density is dual energy X-ray absorptiometry (DXA).

  This test uses special X-ray devices to measure how many grams of calcium and other bone minerals are packed into a segment of bone.

• Urine test. A 24-hour collection of urine can provide information on how well your kidneys function and how much calcium is excreted in your urine.

  This test may help in judging the severity of hyperparathyroidism or diagnosing a kidney disorder causing hyperparathyroidism. If a very low level of calcium in the urine is found, this may indicate a condition that doesn't require treatment.

• Imaging tests of kidneys. Your doctor may order X-rays or other imaging tests of your abdomen to determine if you have kidney stones or other kidney abnormalities.

Imaging tests before surgery

If your doctor recommends surgery, he or she will likely use one of these imaging tests to locate the parathyroid gland or glands that are causing problems:

• Sestamibi parathyroid scan. Sestamibi is a radioactive compound that is absorbed by overactive parathyroid glands and can be detected by a scanner that detects radioactivity.

  The normal thyroid gland also absorbs sestamibi. To eliminate uptake in the thyroid obscuring the uptake in a parathyroid adenoma, radioactive iodine, which is only taken up by the thyroid, also is given and the thyroid image is digitally subtracted.

  Computerized tomography (CT) scanning may be combined with the sestamibi scan to improve detection of an abnormality.

• Ultrasound. Ultrasound uses sound waves to create images of your parathyroid glands and surrounding tissue.

  A small device held against your skin (transducer) emits high-pitched sound waves and records the sound wave echoes as they reflect off internal structures. A computer converts the echoes into images on a monitor.