Checking for gallstones typically starts with recognizing specific symptoms and then confirming with an abdominal ultrasound, which detects stones with about 95% accuracy. Most people begin suspecting gallstones after experiencing a distinct type of upper abdominal pain, but the full diagnostic process can involve blood tests, specialized imaging, and functional scans depending on the situation.
Symptoms That Suggest Gallstones
The hallmark of gallstones is a pain called biliary colic: a steady, intense ache in your mid-upper abdomen or right side, just below the ribs. This isn’t the kind of cramping that comes and goes in waves. It builds, holds, and often radiates around to your back or up under your right shoulder blade. Episodes typically start after eating, especially fatty meals, and can last anywhere from 30 minutes to several hours.
Other symptoms that commonly appear alongside the pain include nausea, vomiting, and sometimes a general feeling of bloating or indigestion that doesn’t respond to antacids. If a stone blocks the bile duct more completely, you may notice yellowing of the skin or eyes (jaundice) and dark-colored urine. These signs point to a blockage that needs prompt attention.
Not everyone with gallstones has symptoms. Stones are frequently discovered by accident during imaging for something else entirely. Current guidelines from the World Gastroenterology Organisation recommend against treating or removing these “silent” stones in most people, since the risk of surgery (which carries a mortality rate of 0.14% to 0.5%) generally outweighs the benefit when you have no symptoms. Exceptions include people living in very remote areas far from medical care, those with suppressed immune systems, or patients already scheduled for abdominal surgery.
Gallstone Pain vs. Other Conditions
Upper abdominal pain has a long list of possible causes, so it helps to know what sets gallstone pain apart. Kidney stones, for instance, cause sharp pain in the lower back or flank that radiates down toward the groin, and they often come with blood in the urine, painful urination, or foul-smelling urine. Gallstone pain sits higher and to the right, radiating upward toward the shoulder rather than downward.
Gastritis and acid reflux can mimic the burning upper-abdominal discomfort, but they tend to improve with antacids and worsen on an empty stomach. Heart-related chest pain can also overlap in location, particularly in women. If your pain is persistent, lasts longer than a few hours, or comes with fever and jaundice, that pattern points more strongly toward a gallbladder problem and warrants urgent evaluation.
Ultrasound: The First-Line Test
An abdominal ultrasound is the standard starting point for diagnosing gallstones. It’s noninvasive, uses no radiation, and takes about 15 to 30 minutes. You’ll typically be asked to fast for 8 to 12 hours beforehand so your gallbladder is full and easier to image. A technician moves a handheld probe across your upper abdomen while sound waves create a picture of your gallbladder and bile ducts on screen.
Ultrasound correctly identifies gallstones in roughly 95.5% of confirmed cases, with a specificity around 90%. That means it catches the vast majority of stones and rarely flags something that isn’t there. It can also reveal signs of gallbladder inflammation, like thickening of the gallbladder wall or fluid around it. Where ultrasound falls short is in detecting very small stones lodged deep in the bile ducts, which sometimes require more advanced imaging.
Blood Tests That Flag a Problem
Blood work doesn’t directly detect gallstones, but it reveals the damage stones can cause when they block the flow of bile. Your doctor will typically order a liver function panel that checks several markers.
- Bilirubin: A waste product normally cleared through bile. When a stone blocks the duct, bilirubin backs up into the blood. Elevated levels, especially of the “direct” fraction, signal a blockage or liver dysfunction.
- Alkaline phosphatase (ALP): This enzyme spikes to four or more times its normal level within one to two days of a bile duct obstruction, regardless of where the blockage is. An isolated rise in ALP with otherwise normal liver numbers can point to a partial or intermittent stone blockage.
- GGT: This enzyme rises alongside ALP during bile flow problems and is actually more sensitive for confirming the blockage is coming from the bile system rather than from bone or other sources.
If your ultrasound is normal but blood work shows elevated liver enzymes, your doctor will likely suspect a stone has already passed or is sitting in the common bile duct where ultrasound has a harder time seeing it.
Advanced Imaging for Tricky Cases
When ultrasound and blood tests leave the picture unclear, two more advanced tools come into play.
MRCP (magnetic resonance cholangiopancreatography) is a specialized MRI focused on the bile ducts and pancreatic duct. It’s more sensitive than both CT scans and ultrasound at finding stones in the common bile duct. The scan is noninvasive and doesn’t use radiation or contrast dye injected into the ducts. It’s typically ordered as a screening step when doctors suspect a duct stone but want confirmation before moving to a more invasive procedure.
ERCP (endoscopic retrograde cholangiopancreatography) is both a diagnostic and treatment tool. A thin, flexible scope is passed through the mouth, down through the stomach, and into the opening of the bile duct. Dye is injected so the ducts show up on X-ray, and if a stone is found, the doctor can remove it during the same procedure. Because ERCP is invasive and carries risks like inflammation of the pancreas, it’s generally reserved for situations where treatment is expected to be needed at the same time, not for diagnosis alone.
HIDA Scan for Gallbladder Function
Sometimes the problem isn’t a visible stone but a gallbladder that simply isn’t working properly. A HIDA scan (hepatobiliary iminodiacetic acid scan) evaluates how well your gallbladder fills and empties. A small amount of radioactive tracer is injected into a vein, and a camera tracks it as your liver processes it into bile and sends it to the gallbladder. You’re then given a hormone or fatty substance to trigger the gallbladder to squeeze, and the scan measures what percentage of its contents it empties.
A normal gallbladder ejection fraction is above 30% to 35%. A number significantly below that suggests chronic inflammation of the gallbladder, even if no stones are visible on ultrasound. This scan is particularly useful when you have classic gallbladder symptoms but imaging keeps coming back clean.
Who Should Get Checked
Certain people are more likely to develop gallstones, and knowing your risk level can help you decide whether to bring up testing with your doctor. The major risk factors include being female, being over 40, having a family history of gallstones, and carrying excess weight, particularly around the midsection. Pregnancy increases risk due to hormonal changes that slow gallbladder emptying. Rapid weight loss, whether from crash dieting or bariatric surgery, is another well-established trigger because it changes the composition of bile.
Diabetes, high triglycerides, and conditions that cause prolonged fasting or require IV nutrition also raise the odds. People with Crohn’s disease or those who’ve had part of the small intestine removed are at higher risk for a specific type of stone called a pigment stone, which forms from excess bilirubin rather than cholesterol.
If you have recurring episodes of upper right abdominal pain after meals, especially pain that lasts more than 30 minutes and doesn’t respond to antacids, that pattern alone is enough reason to request an ultrasound. The test is quick, low-cost, and highly accurate, making it one of the most straightforward diagnostic steps in medicine.