Diagnosis of liver disease typically begins with a physical examination and a medical history that includes a review of medications.

During the examination, a physician may gently press against the abdomen to determine whether the liver is enlarged. A physician may also ask a patient about practices that can lead to liver disease, such as alcohol use, drug use or sexual habits.

A physician may conduct a blood test (test that determines the amount of a substance in the blood and identifies abnormally high or low levels). The presence of certain types of substances in the blood often indicates whether liver damage has occurred. Substances studied during blood tests may include:

• Blood cells. A complete blood count (CBC) measures the amount of the three types of blood cells to detect conditions such as anemia (decreased number of red blood cells), leukopenia (decreased number of white blood cells), leukocytosis (increased number of white blood cells, often due to infection) or thrombocytopenia (decreased number of platelets).
  
  
• Enzymes (complex proteins found in body cells). This is sometimes called a liver function test. Enzymes identified may include alanine aminotransferase (enzyme found mainly in the liver), alkaline phosphatase (enzyme related to the bile ducts) and aspartate aminotransferase (enzyme found in the liver and a few other tissues, such as the heart and muscles).
  
  
• Bilirubin. A substance formed from the breakdown of red blood cells that gives bile its color. A total bilirubin test measures all the bilirubin in the blood and a direct bilirubin test measures a form made in the liver.
  
  
• Proteins. Protein is produced in the liver. Two tests for protein include an albumin test (measures albumin, the main protein made by the liver) and a total protein test (measures albumin and all other proteins in the blood). There are also coagulation tests, which can reveal the insufficient amount of clotting protein that is common in liver disease.

When all tests related to enzymes, bilirubin and proteins are performed, it is called a liver panel.

A physician may also perform imaging tests to identify blockages and other damage to the liver. They may include:

• Ultrasound. An imaging technology that uses sound waves to produce images of the shape and outline of various tissues and organs in the body.
  
  
• Endoscopic ultrasound. A procedure in which a probe that emits sound waves is inserted through the mouth into the gastrointestinal tract to produce images of body tissues.
  
  
• Computed axial tomography (CAT scan). A test that allows for multiple x-rays to be taken from different angles around the patient. It creates images of organs and bones within the body. It may be performed alone or with the use of a special dye (contrast medium).
  
  
• Magnetic resonance imaging (MRI). A safe and noninvasive or minimally invasive imaging test that can help physicians diagnose diseases of numerous organs and vessels. It uses powerful magnets to produce images on a computer screen and film. There may be some concern with recent implanted devices when patients have MRI exams.
  
  
• Endoscopic retrograde cholangiopancreatography (ERCP). A contrast x-ray of the gallbladder, pancreas and liver ducts and other related portions of the biliary system. An endoscope (lighted tube) is inserted through the mouth into the small intestine.
  
  
• Cholangiography. A series of x-rays of the gallbladder and bile ducts using a contrast medium to help detect blockages.
  
  
• Radionuclide imaging. Tests that use small amounts of radioactive material to determine how much bile is flowing through the liver.

Although blood tests and imaging tests provide useful information in the diagnosis of liver disease, a physician may also perform a liver biopsy to confirm a diagnosis. This involves removing a small sample of tissue from the liver and studying it under a microscope. There are several techniques that may be used to remove the tissue. A numbing agent may be applied to the skin and a sedative may be administered before the procedure.