Clinical Use
Diagnosis of pancreatic tumour or a ganglioneuroma which secretes vasoactive intestinal peptide (VIP).
Administration of VIP to animals causes hyperglycaemia, inhibition of gastric acid, secretion of pancreatic bicarbonate and of small intestinal juice, and a lowering of systemic blood pressure with skin flush. These features are seen in patients with a tumour of this type which is secreting VIP.
Patient Preparation
With the patient at rest after an overnight fast, take blood (10 mL) into a syringe.
Sample Preparation
Transfer the blood (10 mL) to a heparin tube (do not exceed 20 U/mL blood) containing Trasylol (aprotinin, 0.2 mL, 2000 KIU). Mix by inversion. Place on ice and transfer to the laboratory. Separate the plasma in a refrigerated centrifuge. Freeze the plasma at -20C within 15 min of venepuncture. Send plasma (5 mL) to the SAS laboratory. Ensure the sample remains frozen during transport. Samples with visible haemolysis will be discarded.
Reference Ranges
Adults: <30 pmol/L;
Patients with VIP-producing tumour: >80 pmol/L.
Centre offering this assay
London Imperial Charing Cross Hospital Endocrine Laboratory