Gallbladder ultrasound: what the scan shows, how it is done and what the results mean

The gallbladder is a small organ in the top part of the tummy that helps you digest food. It sits close to the liver, and bile ducts, which are small tubes, connect it to organs such as the liver and pancreas. An ultrasound scan makes images of these structures using high-frequency sound waves, which bounce back from tissues and are turned into a picture on a screen.

The NHS describes an ultrasound scan as a way of seeing images of the inside of your body, such as muscles, organs or a baby in the womb, usually in a hospital or clinic. A gallbladder ultrasound is simply an ultrasound of the upper right part of the abdomen, with particular attention to the gallbladder, the bile ducts and the nearby liver. It is often reported as part of an abdominal ultrasound.

Because there is no radiation involved, the scan is considered a gentle test. It does not need needles or contrast injections in the usual way, and it can be repeated if the doctors want to check whether something has changed.

The NHS says gallstones are small stones that form in the gallbladder, and that most people who have them do not get symptoms. When a stone blocks a bile duct it can cause tummy pain called biliary colic. The NHS describes this pain as potentially severe, constant, lasting longer than 30 minutes and up to several hours, felt in the middle of the tummy or just under the ribs on the right side, and sometimes with feeling or being sick.

If you have symptoms that could be gallstones, the NHS says you may have an ultrasound scan and a blood test. The scan looks for stones, for thickening or inflammation of the gallbladder wall and for widening of the bile ducts. The blood test can help show whether the liver or pancreas is affected.

An ultrasound can also be requested for other reasons that involve the same area, such as unexplained upper tummy pain, yellowing of the skin or whites of the eyes, or abnormal liver blood results. In some people the gallbladder is not the cause of the problem at all, and the scan helps to show that too.

The NHS says the hospital or clinic should tell you if there is anything you need to do before an ultrasound scan. Instructions differ depending on which part of the body is being scanned, so follow the details in your appointment letter or message rather than assuming a general rule. If the instructions are unclear, ring the department that sent them.

At the appointment you may need to undress behind a screen or change into a gown, or you may only need to move clothing out of the way. You lie or sit on a bed next to the machine. The person doing the scan puts a slippery gel on the skin over the area, then moves a probe across it. The lights may be dimmed to help them see the screen, and you may be asked to change position or hold your breath briefly so that they can see the organs more clearly.

The NHS says you can ask for a chaperone, and that you are in control of the scan and can ask the person doing it to stop at any time. An external ultrasound does not usually hurt, although it may be uncomfortable if the probe is pressed on an area that is already painful. The gel is wiped off with paper towel afterwards and you can get dressed straight away.

A gallbladder ultrasound can show whether stones are present, roughly how many and how large they are. It can also show signs of inflammation of the gallbladder (cholecystitis), and whether the bile ducts look widened, which can suggest a stone has moved out of the gallbladder into the duct.

The NHS says you may be given results at the end of the appointment, or it can take a few weeks, depending on why you had the scan. The report is sent to the doctor who referred you. You might need a follow-up appointment to discuss it, and if you have heard nothing after a few weeks the NHS suggests contacting the specialist or your GP surgery about your results and what happens next.

Sometimes you might need other tests depending on why the scan was done. For example, if the bile ducts look widened, further imaging may be arranged. If you are worried that you do not understand a result, the NHS advises talking to a healthcare professional about it.

If you have symptoms, the NHS says the main treatment is surgery to remove the gallbladder, called a cholecystectomy. If stones are found in the common bile duct you may have a procedure called endoscopic retrograde cholangio-pancreatography (ERCP), in which a thin tube with a camera is passed through the mouth so the opening of the bile duct can be widened and the stones can pass through.

While waiting for surgery the NHS says you may take painkillers such as paracetamol and ibuprofen, be offered stronger painkillers for severe pain, want to avoid foods that cause symptoms and be advised to eat a low-fat diet. People who are more likely to get gallstones, according to the NHS, include those over 40, women, people living with obesity, people with a diet high in fat and low in fibre, people who have lost weight quickly and people with conditions such as diabetes or Crohn's disease.

Complications of gallstones are rare, but the NHS says they can be serious. It advises asking for an urgent GP appointment or getting help from NHS 111 if you have tummy pain lasting longer than 30 minutes. It advises calling 999 or going to A&E if you have sudden severe tummy pain, pain that spreads from the tummy to the back and you are being sick, a very high temperature or feeling hot, cold or shivery, or yellow skin or whites of the eyes.

The NHS adds that yellow skin may be less noticeable on brown or black skin, and that darker pee and paler poo than usual can accompany jaundice. Do not drive yourself to A&E; ask someone to drive you or call 999.

On the NHS, a gallbladder ultrasound is normally arranged by a GP or hospital doctor, and the report goes back to the person who asked for it. Waiting times vary by area and by how urgent the request is. Some people choose to pay for a scan privately to shorten the wait; the technique is the same, but the report should still be sent to your GP or specialist so that the result is linked to the rest of your care.

Whichever route you use, a scan result is only one part of the picture. It is read together with your symptoms, blood tests and examination, and any decision about surgery is made with a surgeon.