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Detects insulin in pancreatic islet cells. Useful for identifying insulin-producing tumors (insulinomas) or islet cell hyperplasia, and for evaluating insulin production in hypoglycemia or diabetes. Cannot distinguish endogenous insulin from exogenous insulin administration.
Collect specimen in a red top or SST tube from a fasting patient. Centrifuge, aliquot serum into plastic vial and refrigerate. Grossly hemolyzed specimens are unacceptable. Fasting specimen, normal volume 1.5 mL serum (minimum 1 mL).
Use cold pack for transport. Make sure cold pack is not indirect contact with specimen.