From the Guidelines
Liver function tests and liver panels are essentially interchangeable terms, with the liver panel being the more commonly used term in clinical settings, as both refer to a group of blood tests assessing liver health and function. According to the most recent study on the topic, published in 2023 in the Journal of the American College of Radiology 1, routine liver chemistries include alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and bilirubin. The study highlights that hepatocellular predominant abnormal liver function tests are reflected as an increase in aminotransferases, ALT, and AST, which can indicate liver damage.
Some key points to consider when interpreting liver function tests or liver panels include:
- Elevated liver enzymes (ALT, AST) typically indicate liver cell damage, with ALT being more specific for liver injury due to its low concentrations in skeletal muscle and kidney 1.
- Increased ALP may occur in cholestatic liver disease, which can show elevated ALP with or without elevated bilirubin, suggesting obstruction of biliary outflow or impairment in bilirubin uptake 1.
- The severity of abnormal aminotransferase can be classified as mild, moderate, or severe, based on the level of elevation above the upper reference limit, with moderate and severe classifications having significant clinical overlap 1.
- Albumin and prothrombin time are actual markers of hepatocellular synthetic function, providing valuable information on the liver's ability to synthesize essential proteins 1.
In clinical practice, the terms "liver function test" and "liver panel" are used interchangeably, and patients should not be confused if their doctor refers to either term when ordering these blood tests. The choice between using the term liver function test or liver panel does not affect the interpretation or clinical significance of the results, as both refer to the same group of tests assessing liver health and function 1.
From the Research
Liver Function Test versus Liver Panel
The terms "liver function test" and "liver panel" are often used interchangeably, but they have distinct meanings.
- A liver panel typically includes a combination of tests that measure various enzymes and proteins in the blood, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and bilirubin 2.
- These tests are often referred to as "liver function tests," but they do not directly measure liver function. Instead, they measure markers of liver injury, which can be hepatocellular or cholestatic in nature 3, 4.
Key Differences
- True liver function tests measure the liver's ability to synthesize proteins, such as albumin and clotting factors, or its capacity to metabolize drugs 4.
- Liver panels, on the other hand, provide a broader picture of liver health by measuring multiple enzymes and proteins in the blood.
- The pattern and severity of liver injury can provide clues about the cause of disease and should guide diagnostic evaluation with serologic testing and liver imaging 2, 5.
Clinical Implications
- Abnormal liver test results should be interpreted in the context of a patient's history and examination, and a systematic, stepwise approach to evaluation and management is recommended 5.
- Quantitative liver function tests, such as the indocyanine green test and galactose elimination capacity, can provide more accurate assessments of liver function, especially in patients undergoing liver surgery 6.
- Nuclear imaging techniques, such as (99m)Tc-galactosyl serum albumin scintigraphy and (99m)Tc-mebrofenin hepatobiliary scintigraphy, can measure both total and future remnant liver function and potentially identify patients at risk for postresectional liver failure 6.