Proper sample collection is critical to sample processing and achieving valid results from the assays. Each principle investigator (P.I.) is responsible for his or her collection. If in doubt as to the appropriate procedure, please contact the core.
Depending upon the specific protocol, a volume of whole blood is usually collected during specific time intervals in an EDTA coated tube. The blood is centrifuged for 15 minutes at 4° C. The plasma is aliquoted into the appropriate size, labeled tube for the core: 12 x75 mm (7 ml pp) for canine and human or 0.5 ml microfuge tubes for mouse. The appropriate protease inhibitor is added to the sample if it is to be assayed for catecholamines, pancreatic polypeptide, glucagons, c-peptide, GLP-1 or active Ghrelin. Please call the core for the specific inhibitor if requiring one of these hormones.
Recommended specimen storage tube for studies: Sarstedt tube (#55.526) 12 x75 mm polypropylene with push caps for human or canine studies. Sarstedt tube (#72.699) 30 x 7.8 mm tubes for mouse samples. Samples should be boxed and organized in the order you wish them to be assayed. If they are bagged, the core will put them in chronological order. Do not use long, bulky labels. The tubes are placed in a robot for pipetting. If the labels are wrapped around the tubes, they will not fit correctly into the rack. Please make your labeling as simple as possible.
Note: Patient labels can be denoted with a date and number. Patient names Are not required.
Samples should be stored at -20 to -80°C. To avoid multiple freeze/thaw cycles, samples must be aliquoted in tubes per assay (i.e. aliquot enough in one tube for insulin, another tube for glucagon, etc.)
Care must be used if heparin is used instead of EDTA as an anticoagulant, since an excess will provide falsely high values in some assays. Use no more than 10 IU heparin per ml of blood collected.
Samples with gross hemolysis or lipemia may yield false results.