The gallbladder is a small, pear-shaped organ located beneath the liver in the upper right abdomen. Its primary function is to store and concentrate bile, a digestive fluid that helps break down fats in the small intestine. Bile is released into the small intestine after a meal, especially one containing fats. Problems arise when the flow of bile is blocked or the organ becomes inflamed, often due to the formation of gallstones. Diagnostic tests are necessary when symptoms suggest inflammation, infection, or obstruction.
Initial Indicators for Testing
Recognizing a pattern of specific physical symptoms is the first step in testing for gallbladder problems. The most common sign is biliary colic, a pain typically occurring in the upper right quadrant of the abdomen. This pain is often triggered an hour or more after eating fatty meals, as the gallbladder contracts against a blockage, and can last for at least thirty minutes.
The pain may radiate to the back, specifically the right shoulder blade or mid-back area. Other indicators include nausea, vomiting, and abdominal bloating or indigestion. During a physical exam, a healthcare provider will look for jaundice, a yellowing of the skin and eyes, which suggests a blockage of the bile ducts.
A specific maneuver, known as Murphy’s sign, is performed by pressing on the upper right abdomen while the patient takes a deep breath. If this causes a sudden halt in inspiration due to sharp pain, it strongly indicates acute inflammation of the gallbladder, known as cholecystitis. These signs prompt the initiation of laboratory and imaging studies.
Diagnostic Blood Tests
Blood tests provide a rapid assessment of internal inflammation, infection, and potential obstruction once a gallbladder problem is suspected. A Complete Blood Count (CBC) is routinely ordered to check for an elevated white blood cell (WBC) count, a common marker of infection or acute inflammation like cholecystitis.
Liver Function Tests (LFTs) measure specific enzymes to determine if bile flow is obstructed. Elevated levels of alkaline phosphatase (ALP) and bilirubin (especially conjugated or direct bilirubin) are strong indicators of a blockage within the bile ducts. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) primarily reflect liver cell damage but may also be elevated due to bile back-up.
Testing amylase and lipase levels is also important to determine if inflammation has spread to the pancreas, a complication known as gallstone pancreatitis. These blood markers offer a biochemical snapshot of the condition’s severity and the extent of organ involvement.
Visualizing Gallbladder Structure
Imaging tests are the primary method for visualizing the anatomy of the gallbladder and the presence of structural abnormalities. Abdominal ultrasound is typically the first-line and most effective test due to its non-invasive nature, accessibility, and high accuracy for detecting gallstones. High-resolution ultrasound can identify gallstones as small as two millimeters and assess the thickness of the gallbladder wall, a key sign of inflammation.
A Computed Tomography (CT) scan is generally not the initial tool for simple gallstones, but it is valuable when complications or other abdominal diagnoses are suspected. The CT scan can detect abscesses, gallbladder perforation, or the spread of inflammation outside the organ. It identifies only about 74 to 79 percent of gallstones, as many are not calcified enough to be clearly seen on a CT image.
Magnetic Resonance Cholangiopancreatography (MRCP) is a specialized MRI that uses fluid within the bile ducts to create detailed, high-resolution pictures. MRCP is highly sensitive for visualizing the bile ducts and is used when a stone is suspected to be lodged there, causing an obstruction. This non-invasive test provides anatomical detail comparable to more invasive procedures, making it a valuable tool for complex cases.
Assessing Gallbladder Function
While structural imaging shows the gallbladder’s appearance, functional tests determine how well it is working, particularly its ability to contract and empty bile. The Hepatobiliary Iminodiacetic Acid (HIDA) scan, also known as cholescintigraphy, is the main test for evaluating function. This procedure involves injecting a radioactive tracer into a vein, which the liver absorbs and excretes with bile.
A special camera tracks the tracer’s movement from the liver, through the bile ducts, and into the small intestine. If the tracer fails to enter the gallbladder, it suggests a blockage of the cystic duct, which is indicative of acute cholecystitis. The HIDA scan can reach an accuracy of up to 95 percent in diagnosing acute inflammation.
The scan is often performed with medicine that causes the gallbladder to contract, allowing for the measurement of the Gallbladder Ejection Fraction (GBEF). A low GBEF, typically considered less than 35 percent, indicates the gallbladder is not emptying properly, a condition referred to as biliary dyskinesia. This finding suggests a motility disorder or chronic inflammation, even when no gallstones are present.