Oral cholecystogram is an x-ray of the gallbladder, an organ in the right upper abdomen that stores bile. The x-ray is taken before the gallbladder releases bile.

The test is used to help diagnose disorders of the liver and gallbladder, especially gallstones. For most purposes, it has been replaced by other tests, such as abdominal ultrasound or gallbladder radionuclide scan.

The test is done in a hospital radiology department or in the health care provider's office by an x-ray technician. The night before the test, you swallow six tablets (one at a time). These tablets contain a special dye (contrast medium) that helps the gallbladder show up better on the images.

At the hospital, you will lie on the x-ray table and will be asked to change position from time to time.

The health care provider may look at your gallbladder with a fluoroscope, an x-ray that can be immediately seen on a TV-like monitor. Then you may be asked to drink a high-fat liquid that will cause the gallbladder to contract and release some bile. X-ray images will be taken at timed intervals.

Tell your doctor if you are pregnant or allergic to x-ray contrast material.

The day before the test you will be asked to eat a high-fat meal (eggs, butter, milk, or fatty meats) at noon. That evening, you should eat a low-fat meal (fruits, vegetables, bread, tea or coffee, and only lean meat).

Two hours after the low-fat meal, take the six tablets, one at a time. After taking the tablets, do not drink anything until after the test.

There is little or no discomfort from the test, although you will probably be hungry and thirsty. Some people experience side effects from the contrast material. There is a slight chance of developing diarrhea.