Patient Preparation: Pentagastrin (0.5 µg/kg) is given by an IV push over 5 seconds. Then a calcium infusion (2 mg/kg) is given IV over 1 minute.
Specimen Collection: Serum is collected as baseline, 1 minute, 2 minutes, 5 minutes, 10 minutes and 30 minutes after infusion.
Side Effects: Rapid infusion reduces the severity of side effects, which are often brief. These include headache, weakness, vomiting, diarrhea, flushing, chest discomfort, lightheadedness and nausea.
Interpretation
Normal: Normal serum calcitonin levels in adults are < 150 pg/mL.
• Following the infusions, patients will show a peak calcitonin level of <= 350 pg/mL in males and <= 94 pg/mL in women.
• The maximum level will be less than 3 times the baseline level. Levels peak at around 2 minutes and are dropping at 5 minutes.
Patients with Medullary Thyroid Carcinoma:
• Patients with normal or borderline increases in calcitonin will show a marked increased in calcitonin levels following stimulation, typically 3-20 (or more) times baseline levels.
Other conditions with increased levels of calcitonin:
(1) other tumors, such as breast or lung
(2) pregnancy
(3) pernicious anemia
(4) subacute thyroiditis
(5) renal failure
