The most important test in checking for a gall bladder cancer is an ultrasound examination. This very simple investigation can be done as an out-patient and simply involves gently rubbing an instrument a bit like a microphone over the upper part of the belly and the lower part of the chest. It is quite painless and only takes a few minutes. The ultrasound uses sound waves to produce a picture of the underlying organs. The scans can also pick up other conditions affecting the gall bladder, like gallstones and benign, non-cancerous tumours, called polyps.

If the ultrasound scan clearly shows that the cancer has spread to other nearby organs and is too advanced for an operation then there may be little need for further tests.

If the ultrasound suggests that an operation might be possible then the next step would be to do a CT scan of the area. This can give more accurate information than an ordinary ultrasound scan about whether or not the cancer has spread to nearby lymph nodes and organs, such as the liver. This will help the specialist decide whether or not to recommend surgery.

Other tests which may give helpful information about the extent of the cancer include:

• endoscopic ultrasound: this uses a special endoscope, a thin flexible telescope, which is passed through the mouth and gullet, into the stomach and then into the small intestine near to the gall bladder. It has a special ultrasound probe and can take ultrasound pictures from inside the body. Before this test a sedative is given to help the person relax.
• endoscopic retrograde cholangiopancreatography (ERCP): this again uses an endoscope, but this time the instrument is used to put dye into the bile ducts and gall bladder so they show up on x-rays. A sedative is also given before this test.
• laparoscopy: this involves a very small operation (this is done under a general anaesthetic), making a cut in the muscle wall of the belly, and introducing a flexible telescope which allows the surgeon to look at the gall bladder and the surrounding organs and check for any obvious signs of tumour spread.

Some blood tests may also be helpful, in particular tests checking for the presence or absence of jaundice. Sometimes serum markers, the presence of certain proteins in the blood which may be linked to the cancer, can also be helpful in making a diagnosis. The two markers which are often raised above normal levels in gall bladder cancer are called CEA and CA 19-9 (although increased blood levels of both these proteins can be caused by other conditions).