Testing
Laboratory Tests
The goals with testing for liver disease are to screen for and detect liver injury, to evaluate its severity, diagnose the cause, and to monitor the liver's status over time. Screening and early detection are important since significant liver damage may occur with few or no symptoms. Diagnosing the cause of liver disease helps to guide Types. The liver is often capable of repairing injuries and resolving inflammation, but conditions that cause obstruction of the bile ducts and/or lead to cirrhosis can cause permanent progressive liver damage. Monitoring the status of a person's liver over time allows measures to be taken to preserve liver function.
Screening, detection, and monitoring
Several liver tests are performed routinely as part of general health screening in a CMP (Comprehensive Metabolic Panel). Essentially the same liver tests may be ordered as a liver panel when someone has symptoms that may be due to liver injury or is at risk for developing liver disease. These tests measure the levels of specific enzymes, bilirubin, or protein that are abnormal when liver injury is present. Tests such as bilirubin may also be ordered individually to monitor a person with a liver disease. If any of the liver tests are abnormal, then they indicate the need for additional evaluation and the use of diagnostic testing that is targeted at what liver condition(s) the doctor suspects a person may have. Screening and detection tests include:
- Alanine aminotransferase (ALT) – an enzyme found mainly in the liver; best test to detect hepatitis
- Alkaline phosphatase (ALP) – an enzyme related to the bile ducts; often increased when they are blocked
- Aspartate aminotransferase (AST) – an enzyme found in the liver and a few other places, particularly the heart and other muscles
- Gamma-glutamyl transferase (GGT) – an enzyme found mainly in the liver; very sensitive to changes in liver function
- Total bilirubin – measures all the bilirubin in the blood; increased with many liver diseases
- Direct bilirubin – measures a form conjugated (combined with another compound) in the liver
- Albumin – measures the main protein made by the liver and tells how well the liver is making this protein
- Total protein – measures albumin and all other proteins in blood, including antibodies made to help fight off infections (antibodies are not made in the liver)
Diagnosis and monitoring
Other tests may be ordered to help diagnose the cause of liver dysfunction. Some are also used to monitor disease status and/or effectiveness of treatment. Testing may include:
- Liver biopsy – a tiny sample of liver tissue is taken to evaluate the structure and cells of the liver; used to help diagnose a wide range of liver diseases
- Hepatitis tests [see Hepatitis A, Hepatitis B, Hepatitis C] – to detect viral hepatitis
- Alfa-fetoprotein (AFP) – may be elevated with liver cancer
- Des-gamma-carboxy prothrombin (DCP) – may be elevated with liver cancer
- Prothrombin time (PT) – to evaluate clotting function
- Iron tests – when hemochromatosis is suspected
- Copper and ceruloplasmin – when Wilson disease is suspected
- Alpha-1 antitrypsin – for alpha-1 antitrypsin deficiency
- Antimitochondrial Antibody (AMA) – to help diagnose PBC (primary biliary cirrhosis)
- Acetaminophen level and/or other Emergency and Overdose Drug Testing – when acute liver failure due to drugs or toxins is suspected
- Complete blood count (CBC) – to evaluate the patient's white and red blood cells and platelets
For more information on laboratory tests used for specific types of liver disease, see the links found in the Table on the Overview page.
Non-Laboratory Tests
- Ultrasound
- CT (computed tomography) scan
- MRI (magnetic resonance imaging)
- MRCP (magnetic resonance cholangiopancreatography)
- PTC (percutaneous transhepatic cholangiogram)
- ERCP (endoscopic retrograde cholangiopancreatography)
For more information on these imaging procedures, see the web site RadiologyInfo.
