What is the purpose of a liver function test? What types of liver function tests are there? What do normal liver function test results look like? How do abnormal results indicate liver problems like alcoholic hepatitis?

Understanding Liver Function Tests

Liver function tests, also known as a liver panel, are a set of blood tests used to measure the performance and health of the liver. These tests analyze various substances in the blood, including proteins, enzymes, and bilirubin, to provide insight into liver function. Healthcare providers often order liver function tests to diagnose or monitor liver-related conditions, such as hepatitis, cirrhosis, and liver damage.

Common Liver Function Tests

There are several key liver function tests that healthcare providers may order, each of which screens for different aspects of liver health:

• Alkaline Phosphatase (ALP): Normal range is 30-120 U/L. Elevated ALP can indicate chronic liver disease, bone disease, or chronic kidney disease.
• Alanine Transaminase (ALT): Normal range is 10-40 U/L. Elevated ALT often indicates liver inflammation, commonly caused by alcohol use, medications, fatty liver disease, or viral infections.
• Aspartate Aminotransferase (AST): Normal range is 10-40 U/L. Elevated AST, along with elevated ALT, typically signifies liver inflammation.
• Gamma-Glutamyl Transferase (GGT): Normal range is 8-40 U/L for females and 9-50 U/L for males. Elevated GGT can be seen in conditions like alcohol use, gallbladder issues, and medication use.
• Albumin: Normal range is 3.5-5.0 g/dL. Low albumin levels may indicate liver disease or malnutrition.
• Total Protein: Normal range is 6.0-8.3 g/dL. Abnormal total protein levels can suggest liver or kidney dysfunction.
• Bilirubin: Normal range is 0.1-1.2 mg/dL. Elevated bilirubin often indicates liver or bile duct problems.
• Lactate Dehydrogenase (LDH): Normal range is 122-222 U/L. Elevated LDH can be seen in various conditions, including liver disease.
• Prothrombin Time (PT): Normal range is 11-15 seconds. Prolonged PT may indicate liver disease or malabsorption of vitamin K.

Interpreting Liver Function Test Results

Abnormal liver function test results can indicate a variety of liver-related conditions. For example, elevated AST and ALT levels often point to liver inflammation, which can be caused by alcohol use, medications, fatty liver disease, or viral infections like hepatitis or COVID-19. Increased ALP levels may suggest chronic liver disease, bone disease, or chronic kidney disease, while elevated GGT can be seen in conditions such as alcohol use, gallbladder issues, and medication use.

Alcoholic Hepatitis and Liver Function Tests

Alcoholic hepatitis is a type of liver inflammation caused by excessive alcohol consumption. Individuals with alcoholic hepatitis may have elevated liver enzymes, such as AST and ALT, as well as increased bilirubin levels. These abnormal liver function test results can help healthcare providers diagnose alcoholic hepatitis and monitor the condition’s progression.

Symptoms of Alcoholic Hepatitis

Individuals with alcoholic hepatitis may experience a range of symptoms, including:

• Yellowing of the skin and eyes (jaundice)
• Upper abdominal pain or swelling
• Nausea or vomiting
• Fatigue
• Loss of appetite
• Dark urine or light-colored stool

Causes of Alcoholic Hepatitis

Alcoholic hepatitis is primarily caused by the long-term, excessive consumption of alcohol. Over time, alcohol can damage liver cells and lead to inflammation, scarring, and impaired liver function. Factors that may increase the risk of developing alcoholic hepatitis include:

• Prolonged, heavy alcohol use
• Binge drinking
• Genetic predisposition
• Malnutrition
• Concurrent viral hepatitis infection

It’s important to note that not all individuals who consume excessive amounts of alcohol will develop alcoholic hepatitis, and the condition can also occur in individuals who do not have a history of heavy alcohol use.