How is Zollinger-Ellison syndrome diagnosed?

Zollinger-Ellison syndrome is characterized by gastrin-secreting tumors, known as gastrinomas, which lead to excessive gastric acid production. The definitive diagnosis of this condition involves measuring elevated levels of gastrin in the blood, as gastrin levels are typically significantly increased in patients with the syndrome. While imaging studies, such as SPECT (Single Photon Emission Computed Tomography) imaging, can assist in localizing the gastrinomas, the elevated gastrin level is a crucial and initial indicator of the disease.

SPECT imaging can help identify where the gastrin-secreting tumors are located, particularly if they have metastasized or are difficult to find, thus making it a complementary diagnostic tool. Together, the combination of an increased gastrin level and SPECT imaging forms a definitive approach to diagnosing Zollinger-Ellison syndrome.

Other options do not provide the necessary information for diagnosing the condition properly. A decrease in gastrin levels would indicate a different physiological condition and is not consistent with Zollinger-Ellison syndrome. The presence of ulcers in the stomach alone does not confirm the diagnosis without correlating evidence of abnormal gastrin secretion. Finally, relying solely on physical examination is insufficient for diagnosing a condition that requires biochemical and