Gastrin - serum

5 mL blood in plain tube.

Patient must be fasting.

Serum should be separated promptly and stored frozen.

If the patient is fasting, and is not taking therapy for peptic ulcer, an elevated level indicates abnormally increased gastrin production.

If the level is 100-500 ng/L, a stimulation test, using either secretin or intravenous calcium, may help to distinguish Zollinger-Ellison syndrome from other causes of hypergastrinaemia eg, atrophic gastritis and pernicious anaemia - consult pathologist.