This test investigates how well the body absorbs bile salts. If they are not being absorbed properly, they interfere with water absorption in the bowel and can cause diarrhoea.

The test takes place over two appointments, booked seven days apart. The first appointment lasts for approximately one hour and the second for fifteen minutes. You may have a light meal before the appointments.

At the first appointment you are given a capsule containing bile salts and a very small amount of radioactivity. Some measurements are taken with a gamma camera before and after having the capsule – you will lie on a special imaging couch for this. At the second appointment the following week, just one measurement is taken to see how much radioactivity is remaining.

After all the measurements have been taken, you are able to go home. The results will be calculated after the second appointment and a written report will be sent to the referring doctor.