What are the risks of an oral cholecystogram?
The risks of an oral cholecystogram are few. One, of course, is the radiation. However, in an OCG there is a relatively small amount of radiation from the x-rays.
Another risk involves the iodine. Some people are allergic to iodine. Fortunately, most people who are allergic know that they are, and therefore do not undergo the test.
When is an oral cholecystogram useful?
The OCG is an excellent procedure for diagnosing gallstones. It finds gallstones 95% of the time. However, the OCG has tended to be replaced by ultrasonography because ultrasonography is slightly better at diagnosing gallstones and can be done immediately without waiting one or two days for the OCG's iodine to be absorbed, excreted, and concentrated. The OCG also cannot give information about the presence of non-gallstone related diseases, which ultrasonography is sometimes able to do. A limitation of the OCG is that it does not work well when there is more than a minimal amount of jaundice. Fortunately, most people with gallstones are not jaundiced.
As would be expected, ultrasonography sometimes finds gallstones that are missed by the OCG. Less frequently, the OCG finds gallstones that are missed by ultrasonography. For this reason, if gallstones are strongly suspected but ultrasonography does not show them, it is reasonable to consider doing an OCG. So OCGs are still done, and for good reason.
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine
"Oral Cholecystography and Sonography of Gallbladder in Cholecystectomy Patients"
U.S. National Library of Medicine, National Institutes of Health