Sample needs to be separated and frozen immediately.
Place the yellow Urgent Gastrin Label on the request form at the time of blood collection.
Gastrin levels can only be interpreted in fasting (>10 hours) patients; nonfasting specimens are uninterpretable
Oxalate, heparin and EDTA are unacceptable sample types.
Grossly Lipemic and haemolsed samples should be avoided.
Increased in Zollinger-Ellison syndrome (ZES) from gastrinoma. In 25% of the cases, gastrinoma is part of the Multiple Endocrine Neoplasma type 1 (MEN type 1) syndrome.
A fasting serum gastrin concentration > 477 pmol/L (1000 ng/L), together with a gastric acid pH <=2 is virtually diagnostic of gastrinoma. However, note that 68% of gastrinoma patients have a fasting gastrin concentration between 47.7 to 477pmol/L (100 to 1000 ng/L) and 0.3-3% even exhibit normal fasting gastrin level. and a stimulation test (secretin or calcium infusion) is required to confirm the diagnosis. These stimulation tests are conducted under fixed protocol and close supervision at Greenlane Endocrinology department.
Other than gastrinoma (sporadic ZES or associated with MEN-1), antral predominant Helicobacter pylori gastritis, pyloric obstruction, post gastric resection with intact antrum (e.g. Billroth type II), renal failure are other causes of increased fasting gastrin concentration with acidic gastric pH <=2.
Causes of hypergastrinaemia with gastric pH >2 include: chronic atrophic gastritis associated with pernicious anaemia or with chronic Helicobacter pylori infection; postvagotomy; use of proton pump inhibitor and H2 receptor antagonist therapy. There 2 classes of acid reduction therapy generally will not cause gastrin level to rise above 400 pmol/L (832 ng/L). Patients must be off these drugs for at least 1 week for valid interpretation of an elevated gastrin. If there is strong suspicion of underlying ZES and worry of precipitating peptic ulcer disease, the proton pump inhibitors may be substitued by a H2 receptor antagonist. Fasting gastrin level is to be measured after withholding oral H2 receptor blocker for 30 hours and withholding intravenous H2 receptor antagonist infusion for 12 hours.
Infection by Helicobacter pylori usually results in about 2 fold rise in basal serum gastrin concentration and up to six fold increase following meal. The raised gastrin concentration generally returns to normal 6 months post eradication therapy.
References:
1. Dhillo et al. Plasma gastrin cannot be used to diagnose gastrinoma in patients on proton pump inhibitors or H2 - receptor antagonists. Ann Clin Biochem. 2006; 43:153.
2. Murgesan SVM et al. Review article: strategies to determine whether hypergastrinaemia is due to Zollinger - Ellison syndrome rather than a more common benign cause. Aliement Pharm Therap 2009; 29:1055-68
Emails to chemicalpathologist@adhb.govt.nz will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours : contact Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Samarina Musaad (Clinical Lead) : SamarinaM@adhb.govt.nz ext. 22402
Dr Cam Kyle: CampbellK@adhb.govt.nz ext 22052
Dr Weldon Chiu: WeldonC@adhb.govt.nz ext. 23427
Dr Campbell Heron: CHeron@adhb.govt.nz ext. 23427
Dr Sakunthala Jayasinghe: Sakunthala@adhb.govt.nz ext. 23427
| Patient preparation |
Fast overnight for > 10 hours |
| Sample |
Serum (Plain) only |
| Sample stability |
Must be separated within 1 hour |
| Sample preparation |
Separate and freeze within 1 hour Minimal volume: greater than 1 mL |
| Transport to LabPlus |
Send frozen |