Liver tests are used to study liver function and to determine if the liver is damaged or inflamed. These tests are done on a blood sample.

Indicators of liver function

• Bilirubin
• Albumin
• Prothrombin time

Indicators of liver damage or inflammation (liver enzyme studies)

• Alanine aminotransferase (ALT)
• Aspartate aminotransferase (AST)
• Alkaline phosphatase
• Lactate dehydrogenase (LDH)

Why It Is Done

These tests are done when your medical history and the findings of a physical exam suggest that you have a condition (such as a viral infection) that might have affected the liver.

Results

Findings of liver tests may include the following.

Normal

All levels are within normal range.

Abnormal

Abnormal liver function tests indicate that the liver is inflamed or is not functioning normally.

Elevated enzyme levels indicate liver inflammation (hepatitis), which may be a clue that a viral infection is present.

What To Think About

Elevated liver enzymes may be caused by something other than mono, including other viral infections (such as hepatitis B); severe bacterial infection; heart disease; heart attack; bone, muscle, and joint injuries; and certain cancers. So liver function tests alone are not a reliable way to confirm a diagnosis of mono.

If your liver enzymes are elevated because of mono, they will return to normal without treatment after the illness goes away.

Complete the medical test information form (PDF)(What is a PDF document?) to help you prepare for this test.