A liver panel is a group of tests that are performed together to detect, evaluate, and monitor liver disease or damage. The liver is one of the largest organs in the body and is located in the upper right-hand part of the abdomen and behind the lower ribs. The liver metabolizes and detoxifies drugs and substances that are harmful to the body. It produces blood clotting factors, proteins, and enzymes, helps maintain hormone balances, and stores vitamins and minerals. Bile, a fluid produced by the liver, is transported through ducts directly to the small intestine to help digest fats or to the gallbladder to be stored and concentrated for later use.
A variety of diseases and infections can cause acute or chronic damage to the liver, causing inflammation (hepatitis), scarring (cirrhosis), bile duct obstructions, liver tumors, and liver dysfunction. Alcohol, drugs, some herbal supplements, and toxins can also pose a threat. A significant amount of liver damage may be present before symptoms such as jaundice, dark urine, light-colored stools, itching (pruritus), nausea, fatigue, diarrhea, and unexplained weight loss or gain emerge. Early detection is essential in order to minimize damage and preserve liver function.
The liver panel measures enzymes, proteins, and substances that are produced, processed or eliminated by the liver and are affected by liver injury. Some are released by damaged liver cells and some reflect a decrease in the liver's ability to perform one or more of its functions. When performed together, these tests give a healthcare practitioner a snapshot of the health of a person's liver, an indication of the potential severity of any liver injury, change in liver status over time, and a starting place for further diagnostic testing.
A blood sample is obtained by inserting a needle into a vein in the arm. For infants, blood may be drawn by puncturing the heel with a lancet.
Some of the tests that may be included in the panel may require fasting overnight with only water permitted. Follow any instructions provided. Inform the healthcare practitioner about all prescription and over-the-counter medications, herbal medications, vitamins and supplements being taken.
Alanine aminotransferase (ALT)
A very high level of ALT is frequently seen with acute hepatitis. Moderate increases may be seen with chronic hepatitis. People with blocked bile ducts, cirrhosis, and liver cancer may have ALT concentrations that are only moderately elevated or close to normal.
Alkaline phosphatase (ALP)
ALP may be significantly increased with obstructed bile ducts, cirrhosis, liver cancer, and also with bone disease.
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Aspartate aminotransferase (AST)
A very high level of AST is frequently seen with acute hepatitis. AST may be normal to moderately increased with chronic hepatitis. In people with blocked bile ducts, cirrhosis, and liver cancer, AST concentrations may be moderately increased or close to normal. When liver damage is due to alcohol, AST often increases much more than ALT (this is a pattern seen with few other liver diseases). AST is also increased after heart attacks and with muscle injury.
Bilirubin
Bilirubin is increased in the blood when too much is being produced, less is being removed, due to bile duct obstructions, or to problems with bilirubin processing. It is not uncommon to see high bilirubin levels in newborns, typically 1 to 3 days old.
Albumin
Albumin is often normal in liver disease but may be low due to decreased production.
Total protein (TP)
Total protein is typically normal with liver disease.
Gamma-glutamyl transferase (GGT)
A GGT test may be used to help determine the cause of an elevated ALP. Both ALP and GGT are elevated in bile duct and liver disease, but only ALP will be elevated in bone disease. Increased GGT levels are also seen with alcohol consumption and with conditions, such as congestive heart failure. .
Lactate dehydrogenase (LD)
This is a non-specific marker of tissue damage. It is usually not elevated with most liver diseases, but it may be elevated with very acute liver disease or liver tumors. It is also elevated with a number of other conditions that do not affect the liver. .
Prothrombin time (PT)
A prolonged or increased PT can be seen with liver disease, vitamin K deficiency, use of drugs to reduce risk of clotting (warfarin), and with coagulation factor deficiencies.
