A parathyroid biopsy is a procedure to remove a small piece of a parathyroid gland. The parathyroid glands are the four glands behind the thyroid in the neck.

A parathyroid biopsy is done while the patient is awake. Using an ultrasound machine, the health care provider locates the gland of concern. A thin needle is inserted directly into the gland, and a small piece of tissue is removed.

The tissue is sent to a laboratory, where it is examined under a microscope. The tissue's levels of parathyroid hormone (PTH) will also be checked. PTH is secreted by the parathyroid glands and helps control the body's calcium levels.

Tell your health care provider if you have any drug allergies or bleeding problems, or if you are pregnant. You must sign a consent form. Also, make sure the health care provider knows about all the medications you are taking.

The test feels like a quick shot (injection). You may feel a sting as the needle is inserted into the gland.

This procedure is most often done to confirm the cause of hyperparathyroidism.

It may also be done if an ultrasound exam shows a larger-than-normal parathyroid gland. Your doctor can only see a parathyroid gland on ultrasound if it is abnormally swollen.

There is no swelling, hormone levels appear normal, and cells from the tissue sample are normal.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The test confirms that a parathyroid gland is enlarged, if hormone levels are too high, or if cells from the sample are abnormal.

Abnormal results may be due to:

• Parathyroid adenoma or carcinoma (rare)
• Parathyroid hyperplasia
• Multiple endocrine neoplasia I (MEN I)
• Multiple endocrine neoplasia II (MEN II)

You can return to normal activities the same day.