If the body doesn't produce cholecystokinin (for some reason), wouldn't the ejection fraction part of a hida scan produce a false negative?

CCK: The body naturally produces cck (cholecystokinin). For hida scan, exogenous cck (sincalide/kinevac) is administered intravenously to cause the gallbladder to contract. The sincalide dose is a weight based dose (per kg of body weight). The sincalide is infused over a specific time period and gallbladder ejection fraction can then be calculated.

CCK is injected: For a hida scan the cck is given by IV injection: sincalide (cck) pretreatment is a c-terminal octapeptide of cholecystokinin (cck), in doses of 0.01–0.02 μg/kg, may be given intravenously, 30–60 min prior to the hepatobiliary tracer injection to minimize the potential for a false-positive study (reference: http://interactive.Snm.Org/docs/pg_ch11_0703.Pdf ) see guideline for more information. -.

No: CCK or cholecystokinin is injected intravenously to cause gall bladder to contract. Inherent CCK does not contribute to the determination of gall bladder disease.