Investigation of patients with achlorhydria or pernicious anemia
Investigation of patients suspected of having Zollinger-Ellison syndrome
Diagnosis of gastrinoma
Specimen Type
Serum
Specimen Requirements
Preferred: Serum Gel
Acceptable: Red Top
Specimen Collection / Processing Instructions
Fasting (8 hours) required
For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins
If medically feasible, proton pump inhibitor (omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, and rabeprazole) therapy should be discontinued 1 week before measurement of serum gastrin levels
Drugs that interfere with gastrointestinal motility (eg, opioids) should be discontinued for at least 2 weeks before serum gastrin testing
Minimum Sample Volume
0.5 mL
Additional Processing Details
If multiple specimens are collected, submit each vial under a separate order
Label specimens with corresponding collection time
Centrifuge at refrigerated temperature within 2 hours of collection and immediately aliquot serum into plastic vial.
Stability
Frozen (preferred): 30 days
Refrigerated: 24 hours
Unacceptable Specimen Conditions
Gross hemolysis
Limitations
Isolated serum gastrin levels can only be interpreted in fasting patients; nonfasting specimens are uninterpretable
Artifactual hypergastrinemia may be observed in fasting patients who have undergone procedures that result in temporary gastric distention or dysmotility (eg, after gastroscopy)
Renal failure prolongs the serum half-life of gastrin and is associated with increased serum gastrin levels
Drugs that interfere with gastric acid secretion, in particular proton pump inhibitors (eg, omeprazole, pantoprazole, dexlansoprazole, lansoprazole, rabeprazole), can lead to significant elevations of serum gastrin levels often above the normal range. These drugs can be discontinued, if feasible, for at least 1 week before serum gastrin measurement in order to avoid gastrin elevation
Drugs that interfere with gastrointestinal motility (eg, opioids) may also interfere with serum gastrin testing
