To diagnose gallstones, your doctor will ask about your symptoms, perform a physical examination and recommend some tests. Tests that can detect gallstones and associated conditions include the following.
Ultrasound scanning is the most common technique used to confirm the presence of gallstones. Ultrasound can:
- detect gallstones in the gallbladder with high accuracy;
- sometimes detect gallstones in the bile ducts (further testing is often needed to confirm stones in the bile ducts); and
- detect signs of gallbladder inflammation.
Ultrasound is a quick and painless procedure that uses high-frequency sound waves, sent through a hand-held device that is moved across the abdomen. The echoes as the sound waves bounce off the gallbladder and other organs are converted to electrical impulses that show a picture on a monitor.
‘Silent’ gallstones, or gallstones that do not cause any symptoms, are sometimes detected incidentally during procedures such as ultrasounds or X-rays.
A HIDA scan – also known as cholescintigraphy or a hepatobiliary scan – involves having a small amount of a radioactive substance (known as a tracer) injected into a vein and then taking scans.
It can be used to detect:
- obstruction of bile ducts (that can be due to gallstones);
- problems with gallbladder emptying; and
- cholecystitis (inflammation of the gallbladder).
Magnetic resonance imaging (MRI) produces detailed images of the body, and can be used to:
- visualise the gallbladder; and
- show gallstones in both the gallbladder and the bile ducts.
Endoscopic retrograde cholangiopancreatography (ERCP)
An investigation called endoscopic retrograde cholangiopancreatography (ERCP) is often performed if a gallstone is suspected to be lodged in the bile duct and cannot be detected using ultrasound.
This procedure involves looking at the bile duct through a small flexible tube called an endoscope, which is inserted into the mouth and directed carefully through the oesophagus and stomach, down into the duodenum (the first part of the small intestine), where the opening of the bile duct can be seen. A dye is then injected through the tube and into the bile duct and X-ray images taken to demonstrate any blockages that may be present.
Sometimes a sphincterotomy is carried out during the ERCP to remove a gallstone from the bile duct. This involves passing a small instrument through the endoscope and making a tiny cut in the lower part of the bile duct. Stones can be removed by collecting them in a tiny basket and removing them through the endoscope.
Blood tests may be used to check for:
- infection or inflammation;
- jaundice (indicated by high levels of bilirubin – a yellowish pigment found in bile and produced in the liver); and
- obstruction of bile ducts (which may be indicated by elevated levels of liver enzymes such as alkaline phosphatase).
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Gallstones (updated 27 Nov 2013). http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/gallstones/Pages/facts.aspx (accessed Aug 2015).
3. MayoClinic. Gallstones (updated 25 Jul 2013). http://www.mayoclinic.org/diseases-conditions/gallstones/basics/symptoms/con-20020461 (accessed Aug 2015).
4. NHS Choices. Gallstones (updated 18 Nov 2013). http://www.nhs.uk/conditions/gallstones/pages/introduction.aspx (accessed Aug 2015).