To have this test it is necessary:

• If the test is necessary in relation to a clinical suspicion of liver stones or stones in the urinary tract, take two vegetable carbon wafers with main meals (two with breakfast, two with lunch and two with dinner) for two days before the test. The day before the test, flush out the intestine (using laxatives), drink plenty of fluids (about 1.5 litres of still water) and have nothing to eat of the day of the test.
• If the test is necessary in relation to a functional pathology, particularly an intestinal occlusion, no preparation is required.
• If the test is necessary in patients treated with dialysis, they must follow the instructions supplied by their doctor with regard to drinking.