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Abdominal Ultrasound: What It Checks and What to Expect
An abdominal ultrasound uses sound waves to image the liver, gallbladder, bile ducts, spleen, kidneys, and portions of the pancreas and aorta. It is painless, uses no radiation, and is commonly ordered to evaluate abdominal pain, abnormal lab results, or suspected gallstones and liver disease.
What organs and structures does an abdominal ultrasound evaluate?
A standard abdominal ultrasound gives your clinician a real-time look at:
Liver. Size, texture, and internal structure. Useful for detecting fatty liver (hepatic steatosis), cirrhosis, liver masses, cysts, and changes consistent with inflammation.
Gallbladder. Gallstones are one of the most common reasons for ordering this test. Ultrasound is highly sensitive for detecting gallstones and gallbladder wall thickening or inflammation (cholecystitis) 1Ref 1National Institute of Diabetes and Digestive and Kidney Diseases (2023).Gallstones.Ultrasound as the primary imaging test for gallstone detection, gallbladder evaluation, and preparation requirements.
Bile ducts. Dilated bile ducts suggest an obstruction — from a stone, stricture, or mass — and warrant follow-up.
Spleen. Enlargement (splenomegaly) can be caused by liver disease, blood disorders, or infection.
Kidneys. Hydronephrosis (swelling from obstruction), kidney stones, cysts, and masses can be visualized. Kidney size and cortical thickness provide information about kidney health.
Pancreas. The pancreas is harder to visualize because it lies behind other structures, but portions are often visible. Significant pancreatic masses or duct dilation may prompt further imaging.
Aorta. The abdominal aorta can be screened for aneurysm, particularly in men aged 65 to 75 who have ever smoked — for whom one-time ultrasound screening is a USPSTF Grade B recommendation 3Ref 3Owens DK, Davidson KW, Krist AH, et al.; US Preventive Services Task Force (2019).Screening for Abdominal Aortic Aneurysm: US Preventive Services Task Force Recommendation Statement.One-time abdominal ultrasound screening for AAA in men aged 65-75 who have ever smoked (Grade B recommendation, published December 2019).
The bowel and stomach are generally not well-evaluated by ultrasound because gas interferes with imaging.
Why might my doctor order this test?
Common reasons a clinician orders an abdominal ultrasound include:
- Right upper quadrant pain — often the first test ordered to look for gallstones or gallbladder inflammation 1Ref 1National Institute of Diabetes and Digestive and Kidney Diseases (2023).Gallstones.Ultrasound as the primary imaging test for gallstone detection, gallbladder evaluation, and preparation requirements
- Abnormal liver function tests (LFTs) — elevated AST, ALT, bilirubin, or alkaline phosphatase
- Jaundice — yellowing of skin or eyes, which can indicate bile duct obstruction or liver disease
- Elevated liver enzymes on routine labs — to screen for fatty liver disease (MASLD/NAFLD), now a common finding 2Ref 2Kanwal F, Neuschwander-Tetri BA, Loomba R, Rinella ME (2024).Metabolic dysfunction-associated steatotic liver disease: Update and impact of new nomenclature on the American Association for the Study of Liver Diseases practice guidance on nonalcoholic fatty liver disease.MASLD/NAFLD as a common reason for liver ultrasound and the context for abnormal liver function test findings
- Suspected kidney stones — particularly when kidney stones are a concern alongside a plain X-ray
- Abdominal pain with nausea or vomiting — to rule out gallbladder or liver causes
- Abdominal aortic aneurysm screening — recommended once for men aged 65 to 75 who have ever smoked 3Ref 3Owens DK, Davidson KW, Krist AH, et al.; US Preventive Services Task Force (2019).Screening for Abdominal Aortic Aneurysm: US Preventive Services Task Force Recommendation Statement.One-time abdominal ultrasound screening for AAA in men aged 65-75 who have ever smoked (Grade B recommendation, published December 2019)
- Monitoring known liver or kidney conditions — serial scans to track changes over time
Your specific symptoms and lab results will determine what your clinician is most looking for.
How do I prepare for an abdominal ultrasound?
Preparation varies slightly by what is being evaluated, but the most common instructions are:
Fasting. Most abdominal ultrasound exams require fasting for 4 to 8 hours beforehand. Food causes the gallbladder to contract, making it harder to evaluate and obscuring gallstones. Gas from digestion can also impair visualization 1Ref 1National Institute of Diabetes and Digestive and Kidney Diseases (2023).Gallstones.Ultrasound as the primary imaging test for gallstone detection, gallbladder evaluation, and preparation requirements.
Water is usually allowed. Plain water generally does not interfere — check with your ordering clinician or the imaging facility.
No special bowel prep is needed. Unlike colonoscopy, no laxative preparation is required.
Loose, comfortable clothing. You will be asked to lift your shirt or change into a gown; comfortable clothing makes this easier.
You may feel gel on your skin. Ultrasound gel is applied to improve sound transmission. It is water-based and washes off easily.
The test itself is typically 20 to 45 minutes and involves a technologist (sonographer) moving a transducer (handheld probe) over your abdomen while you breathe normally or hold your breath on request.
Who reviews the results and what happens next?
The images are interpreted by a radiologist, who sends a formal report to the clinician who ordered the test. That clinician will then discuss findings with you.
Resulting next steps depend on what is found: - Gallstones without symptoms may be monitored or may not require treatment - Symptomatic gallstones typically lead to a referral to a general surgeon for consideration of cholecystectomy (gallbladder removal) 1Ref 1National Institute of Diabetes and Digestive and Kidney Diseases (2023).Gallstones.Ultrasound as the primary imaging test for gallstone detection, gallbladder evaluation, and preparation requirements - Fatty liver typically leads to guidance on lifestyle factors and monitoring, and potentially referral to a gastroenterologist 2Ref 2Kanwal F, Neuschwander-Tetri BA, Loomba R, Rinella ME (2024).Metabolic dysfunction-associated steatotic liver disease: Update and impact of new nomenclature on the American Association for the Study of Liver Diseases practice guidance on nonalcoholic fatty liver disease.MASLD/NAFLD as a common reason for liver ultrasound and the context for abnormal liver function test findings - Abnormal kidney findings may lead to additional imaging (CT or MRI) or referral to nephrology or urology - Liver masses will typically prompt further characterization with CT or MRI
A gastroenterologist (GI specialist) is the appropriate specialist for most liver and biliary conditions. A nephrologist or urologist handles kidney findings. Gale can help you understand your next steps or connect with a Gale primary care clinician who can coordinate your follow-up care.
Common questions
Is an abdominal ultrasound the same as a CT scan?
No. Ultrasound uses sound waves and produces real-time images; CT uses X-rays and provides more detail for complex or deep structures. Ultrasound is typically the first-line test because it involves no radiation, is less expensive, and is very effective for common findings like gallstones.
Will the test hurt?
An abdominal ultrasound is painless. The probe is pressed gently against your skin. If your abdomen is tender from underlying conditions, you may feel some discomfort from that pressure, but the test itself causes no pain.
What if my ultrasound results are normal but I still have pain?
A normal ultrasound is reassuring but does not rule out all causes of abdominal pain. Many GI conditions — including irritable bowel syndrome, peptic ulcers, and esophageal conditions — do not show on ultrasound. Your clinician may order additional tests depending on your symptoms.
Do I need a referral to a GI specialist after an abdominal ultrasound?
It depends on what is found. Your ordering clinician will guide you. For significant liver, gallbladder, or biliary findings, a GI specialist or general surgeon is typically the appropriate next step.
Symptoms that warrant prompt evaluation before scheduled imaging
- —Sudden, severe abdominal pain — do not wait for scheduled imaging
- —Fever with right upper quadrant pain — possible cholecystitis or cholangitis requiring urgent care
- —Jaundice (yellowing of skin or eyes) with pain or fever — urgent evaluation needed
- —Vomiting blood or passing black, tarry stools
Severe abdominal pain, signs of jaundice with fever, or any signs of internal bleeding: go to an emergency department or call 911.
This article provides general information about abdominal ultrasound. A gastroenterologist is the appropriate specialist for GI organ conditions identified on imaging. Your ordering clinician will interpret results in the context of your full clinical picture.
References
- 1.National Institute of Diabetes and Digestive and Kidney Diseases (2023). Gallstones. NIDDK. link ✓Ultrasound as the primary imaging test for gallstone detection, gallbladder evaluation, and preparation requirements
- 2.Kanwal F, Neuschwander-Tetri BA, Loomba R, Rinella ME (2024). Metabolic dysfunction-associated steatotic liver disease: Update and impact of new nomenclature on the American Association for the Study of Liver Diseases practice guidance on nonalcoholic fatty liver disease. Hepatology. doi:10.1097/HEP.0000000000000670 ✓MASLD/NAFLD as a common reason for liver ultrasound and the context for abnormal liver function test findings
- 3.Owens DK, Davidson KW, Krist AH, et al.; US Preventive Services Task Force (2019). Screening for Abdominal Aortic Aneurysm: US Preventive Services Task Force Recommendation Statement. JAMA. doi:10.1001/jama.2019.18928 ✓One-time abdominal ultrasound screening for AAA in men aged 65-75 who have ever smoked (Grade B recommendation, published December 2019)
3 sources, numbered by first appearance. General health information, not medical advice — synthetic demonstration content.