<s>[INST] yes, my daughter has been having problems and doctor said was not gall bladder, but they finally did a hida scan and it showed that her gall bladder was only working at 19%. he sent her to a surgeon and he said these scans were not 100% sure. Can you tell me if they are or not [/INST] Hi there,Thanks for posting in HCM.The EF of gallbladder in HIDA scan should be at least 35%.If it is less than that and symptomatic, then gallbladder has to be removed.HIDA is a good test only to assess the function of gallbladder.Regards. </s>