What Special Specimen Requirements Must Be Met When Collecting and Preparing

What special specimen requirements must be met when collecting and preparing a sample for gastrin analysis?

A) Whole blood is the specimen of choice,collected in EDTA-containing tubes,placed on ice,and then refrigerated immediately upon receipt in the lab.
B) Blood must be collected into a heparin-containing tube,separated in a refrigerated centrifuge,and frozen within 15 minutes of collection.
C) Serum is the specimen of choice and must be collected into non-anticoagulant-containing tubes and kept warm until analysis is complete.
D) A 12-hour overnight collection of gastric juice must be assessed for gastrin.