Doctors use many tests to diagnose a tumor, find out if it is cancerous, and if so, determine whether it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy (the removal of a small amount of tissue for examination under a microscope) is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether a cancerous tumor has metastasized. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
• Type of tumor suspected
• Severity of symptoms
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose a parathyroid tumor:

Surgery. [2] Removing the entire tumor during an operation is the most common way to diagnose both benign and malignant parathyroid tumors. The tumor is then analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). Rarely a biopsy [3] may be done before surgery. In these cases, the doctor usually performs a fine needle aspiration, which removes a sample of fluid and cells from the tumor with a very thin, hollow needle.

Blood/urine tests. Many types of blood or urine tests may be done. The most common test is a serum calcium test. Elevated serum calcium levels can indicate the presence of a parathyroid tumor or hyperplasia (over-active cells) on one or more glands. Another common laboratory test looks for elevated levels of the parathyroid hormone (PTH) and phosphorus levels in the blood. Doctors may suspect parathyroid cancer if these blood tests find a very high level of calcium and/or PTH.

Sestamibi/SPECT scan. A sestamibi/SPECT scan may be ordered if laboratory tests show an elevated level of PTH. A sestamibi/SPECT scan is a procedure in which a specific protein, called sestamibi, is mixed with a radioactive material and injected into the patient’s vein. A parathyroid tumor will absorb the material, and the tumor will be visible on an x-ray of the neck. SPECT stands for single proton emission computerized tomography.

Ultrasound [4]. An ultrasound uses sound waves to create a picture of the internal organs. For tumors in or around the thyroid gland, an ultrasound is very useful.  However, it has limitations if the tumor is located lower in the neck or upper chest.

Computed tomography (CT or CAT) scan [5]. A CT scan creates a two-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail. The three-dimensional CT scan for parathyroid tumor localization is a “timed infusion” of contrast and, when combined with a sestamibi/SPECT scan (see above), is considered the “gold standard” in parathyroid imaging today.

Magnetic resonance imaging (MRI) [6]. An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.

Learn more about what to expect when having common tests, procedures, and scans [7].

After these diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the tumor; this is called staging [8]. Learn more about the first steps to take after a diagnosis [9].