Asymptomatic gallstones are often found by chance during investigations of unrelated conditions14.
If you have symptoms and gallstones are suspected, your GP will ask you about the symptoms you are experiencing and may feel your abdomen to see if your liver or gallbladder is tender or enlarged. Blood tests are usually the next tests that your GP will carry out.
A sample of blood is taken by your doctor or a nurse and sent for analysis. These blood tests will look for signs of infection or inflammation. Additional blood tests known as liver function tests (LFTs) will also be done and will look for indications of inflammation, blockage of the bile ducts and damage to the liver.
The liver produces many chemicals that pass into the bloodstream; these can alter if your liver is inflamed or if bile ducts, carrying bile from the liver, are blocked. In the case of suspected gallstones, high levels of alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and serum bilirubin will usually be seen3,17.
If you are found to have an abnormal result, or a strong clinical history (a family history of gallstones, previous gallbladder surgery or you have risk factors for gallstones), then your GP will refer you for further tests, such as an ultrasound scan, to confirm your diagnosis4.
Ultrasound
Most stones, in the gallbladder, can be clearly seen on an ultrasound scanner. An ultrasound scan is a routine procedure; the same technology is used in pregnancy. It is usually performed in the X-ray department of the hospital or in an outpatient’s clinic. The procedure is very safe and should not be painful, but it may take 10 to 15 minutes to complete.
Before the scan, you may be asked not to eat or drink anything for about six hours so that your gallbladder is full of bile, as this helps to view the gallbladder more clearly. You will be asked to uncover the top of the right half of your abdomen (below your ribs) and lie on your back. Gel will be applied to your skin which may feel slightly cold. A probe will be moved across the surface of your skin. The gel helps to make this movement easier and makes sure that sound waves can be directed through your skin as the probe passes over your liver area. Anything solid will cause the sound wave to be reflected back via the probe and will be turned into an image that can be seen on a screen. Sometimes you may be asked to move into a different position so that your gallbladder can be clearly seen on the screen.
ERCP (endoscopic retrograde cholangiopancreatography)
If you have developed jaundice and doctors suspect that stones have passed into your pancreas or bile ducts, a procedure known as ERCP may be undertaken. An ERCP gives a detailed X-ray of your pancreas and bile ducts. You will be given a sedative injection to make you feel sleepy and a little oxygen to help you breathe easily during the test. The test uses a dye (a radiopaque substance) that shows up on X-rays. The dye will either be injected into your bloodstream so that it concentrates in your bile ducts and gallbladder, or inserted into your bile ducts using the endoscope (a long, thin flexible tube with a camera at the end) which is passed through your mouth and into your stomach and intestine.
X-ray images are then taken. These X-rays will show any abnormalities in the flow of your bile (such as a blockage where a gallstone may be present) or in your pancreatic system (such as an inflamed gallbladder or pancreas). The dye passes out of your body harmlessly when you pass water. The whole test may last from 15 to 30 minutes and most people remember nothing about it afterwards because of the sedative injection1. If a stone or blockage is found, your doctor may try to remove it at this point to prevent further intrusion (see ‘Treatment’ section).
MRCP (magnetic resonance cholanglopancreatography)
Another scan you may have, if you are suspected of having gallstones in your bile duct, is an MRCP. This uses a strong magnetic field and radio waves to create an image of your liver, bile ducts, gallbladder and pancreas.
An MRCP scan is performed in a tunnel about 1.5 metres long, surrounded by a large circular magnet. You will be asked to lie on a couch and may be given an injection of contrast dye (a substance that will help to enhance the images).The couch will then move into the tunnel and a series of images will be taken. The scan will take 15 – 40 minutes and is not painful18.
Other tests
There are other types of examination however these are not routinely used in the majority of hospitals for the detection of gallstones19. These include CT (computerised tomography), endoscopic ultrasound and HIDA (Hydroxyl Iminodiacetic Acid) or TBIDA (Trimethylbromo Iminodiacetic Acid) scans.
In a HIDA or TBIDA scan, an injection of a minute dose of a harmless radioactive material is given which shows up under a special camera,if your gallbladder is working properly. The radiation dose from this type of examination is no different from having an ordinary X-ray. This examination may be used to look for acute cholecystitis.
It is possible for the gallbladder to become inflamed when no gallstones are present. This may be because your gallbladder is not filling and emptying bile fully, causing a build up of pressure and pain in your abdomen. In order to diagnose this, you may be offered a HIDA or TBIDA scan, as above, but with the addition of either, the hormone cholecystokinin (CCK) or the ingestion of a fatty meal to stimulate your gallbladder to contract. The rate at which your gallbladder is able to expel bile is measured, and if only a small amount is expelled, treatment for a dysfunctional gallbladder may be recommended20.