• Sometimes the presence and location of a primary parathyroid tumor can be confirmed by placing a catheter
  into the veins draining the parathyroids or metastatic deposits. Blood samples are then taken from each site
  and serum parathyroid hormone levels are determined.

Imaging 
• Reabsorption of bone on x-ray, or osteopenia (loss of bone) by bone density tests.
• Localization tests can be done before surgery. These include Sestamibi, CT, or MRI scans of the neck and
  mediastinum .
• Localization tests are especially helpful in patients with persistent or recurrent disease, or in patients who
  have had previous thyroid surgery.