Tests and diagnosisBy Mayo Clinic staff
Your doctor will base a diagnosis on the following:
- Medical history. Your doctor will ask about your signs and symptoms and review your medical history. If you have a blood relative, such as a sibling or parent, with MEN I, it's more likely that you have Zollinger-Ellison syndrome.
- Blood tests. A sample of your blood is analyzed to see whether you have elevated gastrin levels. While elevated gastrin may indicate tumors in your pancreas or duodenum, it also can be caused by other conditions. You'll have to fast before this test and may need to stop taking any acid-reducing medications to get the most accurate measure of your gastrin levels. Because gastrin levels can fluctuate, this test may be repeated a few times.
- Gastrin level measurement. Since elevated gastrin levels can be caused by conditions other than Zollinger-Ellison, your doctor may test the acidity of the stomach to clarify which condition is elevating your gastrin levels. Gastrin levels also can be elevated if your stomach doesn't make acid or if you're taking medications that block acid. If your stomach is making acid, your doctor may perform a secretin stimulation test. For this test, your doctor measures your gastrin levels, gives you an injection of the hormone secretin and measures gastrin levels again. If you have Zollinger-Ellison, your gastrin levels will increase even more.
- Upper gastrointestinal endoscopy. After you're sedated, your doctor inserts a thin, flexible instrument with a light and video camera (endoscope) down your throat and into your stomach and duodenum to look for ulcers. Through the endoscope, your doctor may remove a tissue sample (biopsy) from your duodenum for examination to help detect the presence of gastrin-producing tumors. To prepare for the test, your doctor will ask you not to eat anything after midnight the night before the test.
- Imaging studies. Your doctor may use imaging techniques such as a nuclear scan — which uses radioactive tracers to help locate tumors — CT, ultrasound or MRI.
- Endoscopic ultrasound. In this procedure, your doctor examines your stomach and duodenum with an endoscope fitted with an ultrasound probe. The probe allows closer inspection of the digestive tract, making it easier to spot tumors. It's also possible to remove a tissue sample through the endoscope. You'll need to fast after midnight the night before this test, and you'll be sedated during the test.
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- Miller LJ (expert opinion). Mayo Clinic, Rochester, Minn. Aug. 10, 2012.