What Is a Gallbladder (HIDA) Scan?

Medically Reviewed by Jabeen Begum, MD on December 08, 2023
8 min read

Pain in your upper right belly a couple of hours after a large or fatty meal is one of the first signs that you may have gallstones. To figure it out, your doctor may want you to have a test called a hepatobiliary iminodiacetic acid (HIDA) scan. It's also known as cholescintigraphy or hepatobiliary scintigraphy. A HIDA scan shows how well your biliary tract is working, especially your gallbladder. 

Your biliary tract is a system of organs and ducts that makes, stores, and moves digestive juices (bile and pancreatic enzymes) to your small intestine to help you break down and absorb the nutrients in your food. It's made up of your liver, bile ducts, gallbladder, pancreas, and small intestine. Most of the organs of your biliary tract are in your upper belly. 

Since the organs in your biliary tract are important for digestion and so closely connected, anything that stops or slows the flow of bile will likely affect your whole digestive system. A HIDA scan can help your doctor figure out what's causing your symptoms.

Your gallbladder is a small organ that sits under your liver in the upper right part of your belly. It stores bile, a digestive fluid that your liver makes, and releases it into your stomach to break down fats and help with digestion.

Your doctor may order a HIDA scan when:

  • You have severe stomach pain, especially on your right side
  • You have pain or fever after you've had surgery on your gallbladder or upper gastrointestinal tract or a liver transplant
  • Newborns have severe jaundice (when their skin and eyes turn yellow) 

Conditions that your doctor may be able to diagnose with a HIDA scan include: 

Gallstones (the most common reason for a HIDA scan). Gallstones are hardened clusters of bile that develop in your gallbladder. They can vary in size, from as small as a grain of sand to as large as a golf ball. Smaller gallstones may move around and then get stuck in your bile duct, which may cause a blockage.

Cholecystitis , which is a swollen gallbladder, usually due to gallstones

Sphincter of Oddi dysfunction. The sphincter of Oddi is a muscle that opens and closes to control the flow of bile and other pancreatic juices into your small intestine. If your sphincter of Oddi doesn't open when it's supposed to, it can make your digestive juices back up. This can cause severe pain in your stomach.

Blocked bile ducts (biliary atresia). This can happen in newborn babies and cause liver damage if they don't have surgery to place a shunt (a tube that allows the bile to flow) in their gallbladder.

Biliary leak. This may happen after an injury to your belly, or after gallbladder surgery or a liver transplant. 

Your doctor may also check to make sure a stent is working with a HIDA scan if you've had a biliary stent placed. A stent is a small, hollow tube that holds your bile duct open if it's blocked. Also, if you’ve had a liver transplant, you may need several HIDA scans over time to make sure your new liver is working as it should.

Before you have a HIDA scan, tell your doctor:

  • If you are pregnant, think you may be pregnant, or are nursing
  • About any allergies, recent illnesses, or other medical conditions you have
  • If you have had tests that used barium within the last 48 hours
  • If you have a fear of closed or tight spaces (claustrophobia)

Most of the time, your doctor won't test you with a HIDA scan when you're pregnant. If you're nursing, you may want to pump extra milk and store it before the test. You'll have to throw your milk away for 24 hours after the test. This is because your milk may have radiation in it from the radiotracer the test uses to trace the flow of bile in your biliary tract.

Newborn babies may need to be pretreated for 3-5 days before the scan. Your baby's doctor will give you instructions before the test if that's the case.

Leave your jewelry and accessories at home, because wearing these can get in the way during the test.

Your doctor will help you understand how to get ready for your procedure. But, in general, you should:

Stop certain medicines. Tell your doctor ahead of time about any medications, including vitamins and herbal supplements, you take on a daily basis. Some medicines keep a HIDA scan from working well, including:

  • Atropine, a medicine that reduces the amount of saliva you produce. You might get this during surgery or to treat some cases of poisoning.
  • Benzodiazepines (such as Ativan, Klonopin, and Xanax), a class of medicines used to treat seizures, anxiety, and some other mental health conditions
  • Indomethacin, a nonsteroidal anti-inflammatory drug (NSAID) used to control joint pain and swelling in people with osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis
  • Nifedipine, a calcium channel blocker used to treat high blood pressure and control chest pain
  • Birth control pills
  • Octreotide, a medicine that reduces the amount of growth hormone you produce. It's used to treat acromegaly, carcinoid tumors, and vasoactive intestinal peptide secreting adenomas (VIP-omas). 
  • Theophylline, a medicine that relaxes and opens airways in the lungs. It's used to prevent symptoms of asthma, chronic bronchitis, emphysema, and other lung diseases.

If you take any of these, your doctor may ask you to hold off on taking them until your scan is over.

Fast. You’ll need to avoid eating or drinking for at least 4 hours before your test.

Follow your doctor’s orders. They may prescribe a special medicine that’ll help the HIDA scan get better images of your organs. You may need to start taking it a few days before your scan. Or a technician might give it to you right before your test begins.

You may have the test in an outpatient center or in the radiology department in a hospital.

During the test, you’ll lie down on an imaging table. A technician will give you a special radioactive chemical (radiotracer), usually through an IV in your arm. It shouldn’t hurt, but it may feel cold. You might also feel a little pressure as the chemical enters your bloodstream.

Next, the technician will place a special camera over your belly. As the chemical “traces” the path that bile takes through your liver and into your gallbladder and small intestines, the camera will take images along the way. The camera may be fixed in position or it may rotate around you. To get the best pictures, you need to stay as still as you can during the test.

HIDA scan with cholecystokinin

You might also receive other medicines during the test to help the technician get better images of your gallbladder. For instance, you may get a chemical called cholecystokinin (CCK), which is a hormone your body makes that helps you digest proteins and fats. It'll cause your gallbladder to empty, which may cause cramps in your upper belly. 

How long do HIDA scans take?

The test usually takes 1-4 hours. You’ll need to stay still during this time. If not, the pictures of your gallbladder will be blurry, and you’ll have to do the scan again. Some people may need to come back for more imaging after about 24 hours.

Is a HIDA scan painful?

A HIDA scan is painless, but you may feel a sting or pinch when the technician puts the IV in your arm. However, you may have pain due to the condition your doctor is testing you for. And you may not be able to take pain medicine during the test because some of these can cause changes in your biliary system that would interfere with the test. For instance, you need to stop taking opiates (such as morphine and codeine) for at least 6 hours before the test because they can make it look like you have a blockage when you don't.

After your HIDA scan, you shouldn’t need a lot of time to recover. Most people go on to have a normal day. Over the next 24 to 48 hours, you’ll pee and poop out the radioactive chemical. Drink plenty of water to help remove it from your body faster. Also, flush the toilet right after you use it and wash your hands really well with soap and water.

If you're nursing, throw away your milk for 24 hours after the scan.

You may have different information on your HIDA scan report, depending on why you're being tested. At the least, your report will explain how the radiotracer moved through your biliary system.

Normal HIDA scan

You will get this result if the radiotracer moved freely from your liver and into your gallbladder and small intestine. This usually means that your gallbladder is working the way it should and is an average size and shape.

Abnormal HIDA scan

Your doctor will explain the results to you. Be sure you ask questions if you don't understand anything. 

If you had an abnormal HIDA scan, you may get one of the following on your report:

  • Slow movement of the radiotracer, which suggests that you have a blockage or that your liver isn't working well
  • No radiotracer seen in the gallbladder, which suggests that you have swelling in your gallbladder due to a blockage
  • Abnormally low gallbladder ejection fraction, which suggests you've had swelling in your your gallbladder for a while
  • Radiotracer detected in other areas, which suggests you've got a leak in your bile ducts

The radiotracer you're given during the test has only a small amount of radioactivity (about the same amount as a CT scan of the head), and it's only radioactive for a few hours. After that, it’s harmless. The camera that’s used to take pictures of your organs doesn’t give off any radiation.

Doctors believe a HIDA scan is safe, but there’s a small chance of side effects, which include:

  • A rash or bruising at the site of the IV
  • An allergic reaction to the radiotracer or the other medications you received during the scan (very rare)

If you have questions about an upcoming HIDA scan, be sure to talk to your doctor. And be sure to tell your doctor if you're pregnant, think you may be pregnant, or are nursing. Though you are only getting a small amount of radioactive material during the test, it can potentially harm your baby. 

A HIDA scan is a test your doctor may order to help them figure out if you've got something wrong with your gallbladder, liver, or bile ducts. You'll likely get your test in an outpatient center or hospital radiology department. It's a painless and relatively short test that uses a tiny amount of radioactive material to help your doctor see how bile moves through your digestive system.