What tests are done to detect gallstones?
Gallstone disease can develop in many different ways. A number of tests may be used to establish the diagnosis:
- Ultrasound: Ultrasound testing uses sound waves to take images of the gallbladder. It is the gold-standard to look for gallstones because it is simple and non-invasive. Ultrasound is very good at highlighting gallstones within the gallbladder, as well as features, such as a thickened gallbladder wall, that point to inflammation of the gallbladder (acute cholecystitis).
- Liver function tests (LFTs): Although these tests are not done specifically for gallstone disease, a simple blood test looking at the enzyme levels in the liver can show inflammation in the gallbladder caused by gallstones. Other combinations of liver tests are arranged if gallstones fall out of the gallbladder and are blocking the bile duct, which can lead to jaundice (the skin, whites of the eyes and mucous membranes turn yellow).
- Complete blood count (CBC): If there is inflammation caused by gallstones, the white blood cell count is usually elevated (higher). In this situation, the patient will often have a fever.
- Computed tomography (CT): This test uses X-rays to construct detailed images of the abdominal organs. CT can give additional information on the bile ducts and liver, which may be affected by gallstone disease.
- HIDA scan (cholescintigraphy): During this test, a radioactive material called hydroxy iminodiacetic acid (HIDA) is injected into the patient. The material is taken up by the gallbladder and shows how the gallbladder is functioning. This test is useful when the ultrasound result is inconclusive, especially if there is acute inflammation of the gallbladder and the outlet of the gallbladder is blocked. It is also beneficial when the gallbladder is diseased but there are no stones present (acalcalous cholecystitis).
- Magnetic resonance cholangiopancreatography (MRCP): This test uses magnetic resonance imaging (MRI) to produce detailed pictures of the biliary tree (liver, gallbladder and bile ducts). It is of particular use to look at the bile ducts for signs of stones that have escaped from the gallbladder and are blocking the bile duct, which can lead to jaundice.
- Endoscopic retrograde cholangiopancreatography (ERCP): In this procedure, a tube is placed down the patient’s throat, into the stomach, then into the small intestine. Dye is injected and the ducts of the gallbladder, liver, and pancreas can be seen on X-ray. ERCP is now mainly used to treat patients in whom a gallstone has blocked the bile duct causing pancreatitis (inflammation of the pancreas), jaundice or cholangitis (infection of the bile).