An Introduction To The Gallbladder
The gallbladder is located with the abdomen in the upper right quadrant. It is just below the liver and is joined to the liver by the common bile duct. The main function of the gall bladder is to store bile and wastes that has been produced by the liver. The body uses the bile during the process of fat digestion. The bile made by the liver is a greenish fluid that also contains bilirubin. Bilirubin is a chemical used to emulsify fats, and the gall bladder will contract and release bile in the presence of fat molecules in the small intestine.
Since the liver and gallbladder are closely tied together in structure and function, various disorders of the gallbladder can also be diagnosed by testing the function of the liver, and vice versa.
A Description of the Gallbladder Function Tests
- CBC Blood Count: One of the first tests the physician can order will measure the level of cells within the blood. This test can tell if a high amount of white blood cells is indicative of an infection.
- Abdominal X-ray: This is one of the first test the physician is likely to order after the blood test. An x-ray is able to show if the gall bladder is inflamed or enlarged, or if there are gallstones present.
- Ultrasound: An ultrasound is also completed to check if the gallbladder is inflamed of if a gallstone is blocking the bile ducts and causing the patient’s symptoms. An ultrasound uses a diagnostic probe that is passed along the surface of the abdomen to view the organs inside.
- CT Scan: In some instances a CT scan can be ordered if the patient’s signs and symptoms are difficult to diagnose.
- Liver Enzymes: In regards to liver function tests, the levels of three main enzymes are checked. The first enzyme is alanine transaminase (ALT). It is used in protein digestion and its blood level can rise in abnormal gallbladder function after inflammation or injury. The second liver function test used to diagnose problems with the gallbladder is the alkaline phosphatase (ALP). It is also found within the gallbladder, and the level of this enzyme will increase in the blood if the gallbladder is not functioning correctly. Another enzyme that can be used to tests both liver and gallbladder function is aspartate aminotransferase (AST). Like ALT, AST can also be released from the gallbladder if there is injury or infection. However, ALT levels are more specific to the gallbladder than AST as AST is also released from heart muscle.
- Bilirubin: Another blood test the physician can order is the bilirubin test. Bilirubin found in bile, and is responsible for fat emulsion, and its presence gives the bile that green-yellow color. When there is a large amount of bilirubin in the blood, the person will have a yellow tint to the skin as in the case of jaundice. Bilirubin is formed after the breakdown of red blood cells by the liver, and the hemoglobin the cells contain is transformed to bilirubin and stored in the gallbladder.
- Magnetic Resonance Cholangiopancreatography: This is one of the less common gallbladder function tests, but sometimes it is preferable because MRI does not expose the body to radiation like an x-ray does. This particular technique is used to check for blockage by imaging the ducts of the liver, gallbladder, and pancreas.
- HIDA scan: This involves the use of hydroxy iminoacetic acid, which is a radioactive material used to image the structure of the gallbladder for any abnormalities. However, this is a less common test used to determine gallbladder function.
Print Source: Davidson, Stanley & C. Haslett. 2002. "Davidson’s Principles and Practice of Medicine.” Churchill Livingstone, Edinburgh.
Print Source: Cotran R, Kumar V, and Robbins, SL. 1999. Robbins Pathologic Basis of Disease, 6th Ed. W.B. Saunders Company, Philadelphia.