The calcitonin test is primarily used to help diagnose C-cell hyperplasia and medullary thyroid cancer, to evaluate the effectiveness of treatment, and to monitor those affected for recurrence. It is also ordered to screen for medullary thyroid cancer in family members of people with multiple endocrine neoplasia type 2 (MEN 2).
Stimulation tests are more sensitive than calcitonin measurements alone. This involves collecting a baseline sample, then giving a person an injection of intravenous calcium or pentagastrin to stimulate calcitonin production. Several more blood samples are then collected over the next few minutes to measure the effect of the stimulation. People with early C-cell hyperplasia and/or medullary thyroid cancer will usually have very significant increases in their levels of calcitonin during this test.
Calcitonin levels may be ordered when someone is suspected of having C-cell hyperplasia or medullary thyroid cancer. A person may experience signs and symptoms, such as:
A lump or swelling at the front of the neck
Pain at the throat or front of the neck
A change in the voice, hoarseness
Difficulty swallowing or breathing
Persistent cough not associated with a cold
A recent study also recommended measuring calcitonin before surgery in all people with thyroid nodules, but not all clinicians agree. Stimulation tests may be ordered when someone has indeterminate or normal calcitonin results but clinical suspicions remain. Calcitonin tests may be periodically performed on family members of those who have MEN 2, starting at an early age, in order to detect medullary thyroid cancer or C-cell hyperplasia as early as possible. When someone has been treated for medullary thyroid cancer, calcitonin testing will usually be ordered at regular intervals to monitor treatment effectiveness and recurrence.
A low level of calcitonin means that it is unlikely that symptoms are due to C-cell hyperplasia or medullary thyroid cancer.
An elevated concentration of calcitonin means that excessive amounts are being produced. Significantly elevated levels of calcitonin are a good indicator of C-cell hyperplasia or medullary thyroid cancer; however, the doctor will use other procedures, such as a thyroid biopsy, scan, and ultrasound, to establish the diagnosis.
With successful treatment for medullary thyroid cancer, which may involve removal of the thyroid gland and often some surrounding tissues, calcitonin levels will usually fall to very low levels. If the values stay low over time, then it is likely that the treatment was effective. In some cases, calcitonin levels will fall but remain moderately elevated after treatment. This means that some calcitonin-producing tissue remains. Doctors will monitor calcitonin and watch for increases over time. If calcitonin levels begin to rise, then it is likely that there is a recurrence of medullary thyroid cancer.
With medullary thyroid cancer and C-cell hyperplasia, other thyroid tests, such as T4, T3, and TSH, are usually normal while calcitonin levels are elevated.
Calcitonin levels may be elevated with lung, breast, and pancreatic cancers, insulinomas, and rare pancreatic tumors called VIPomas (associated with vasoactive intestinal peptide (VIP) hormone production). Concentrations of calcitonin may be increased with drugs such as epinephrine, glucagon, and oral contraceptives, and are normally higher in newborns and in women during pregnancy.
This article was last reviewed on March 6, 2012. | This article was last modified on July 18, 2013.
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