An ultrasound of the gallbladder will show gallstones, polyps or sludge (which is thickened bile). We also look for gallbladder enlargement, thickened wall or fluid within the wall of the gallbladder. These are all indications of an infected or diseased gallbladder. Usually someone with gallbladder disease complains of right upper abdomen pain, back and chest pain, nausea and vomiting, certain food intolerances and sudden changes in bowel habits. This test lasts approximately 20 minutes and requires the patient to fast six to eight hours prior to the test.