Doc ordered a HIDA scan. Just talked to radiology and they said I will drink Ensure instead of CCK. Is this normal and will this give accurate result?

Ensure vs CCK. A HIDA scan is used to assess biliary function, including uptake of a radiopharmaceutical by the liver, excretion into the bile ducts and gallbladder, and finally gallbladder "ejection fraction," or how well the gallbladder contracts. To cause gallbladder contraction, CCK can be injected intravenously, or the patient can be given 8 oz of Ensure to drink over a short period of time. Each works well.
Yes. There is national shortage of Kinevec ( a cholecystokinin analogue) which is given IV as part of the provocative HIDA study. An oral fatty meal like Ensure (or a milkshake) will work just as well but might take 20 or 30 minutes longer. In fact, if it is normal it would also demonstrate normal gastric emptying and absorption of the fatty meal. More physiologic than IV to reproduce symptoms too.