How Hepatitis Is Diagnosed

Depending on the cause and how advanced the disease is, hepatitis typically is diagnosed with a combination of blood work, imaging tests, and liver biopsy. If viral hepatitis is suspected, blood tests are run to detect the presence of a specific hepatitis virus or for antibodies produced by the immune system to fight that virus. Blood tests to look for signs of liver damage may also be used to diagnose viral hepatitis, as well as the non-viral types. More extensive testing may be used to help fully diagnose and assess hepatitis of all types.

Symptoms that might prompt a doctor to suspect a patient has hepatitis include flu-like or gastrointestinal symptoms, along with jaundice (yellowing of the skin or whites of the eyes, dark urine, or pale stools). These symptoms, plus a medical history and physical exam, are likely to result in the ordering of blood tests.

The blood can provide a great deal of information about how well the liver is working. A liver function test, or liver panel, is used to look for markers of liver disease caused by hepatitis, such as elevated bilirubin (a by-product of blood that's responsible for jaundice) and certain liver enzymes that help with essential functions.

Normally, the liver keeps tight control of these enzymes. But when it's damaged, enzymes can escape into the blood where they can be detected in a small sample drawn by your healthcare practitioner.

The three most common enzymes tested for when liver damage is suspected are:

• Alanine aminotransaminase (ALT)
• Aspartate aminotransferase (AST)
• Gamma-glutamyl transaminase (GGT)

The immune system makes two types of antibodies specific to individual viruses: As soon as the body identifies one, it produces IgM antibodies to fight that specific virus. Toward the end of infection, the body produces IgG antibodies that also are specific to the virus but function to provide future immunity.

Tests exist for both IgM and IgG antibodies specific to three hepatitis viruses: hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV).

In addition to detecting antibodies for HBV and HCV, tests called polymerase chain reaction, or PCR, tests can be used to directly measure the amount of virus in the blood.

Although imaging tests cannot detect a viral infection of the liver, certain ones can reveal inflammation, changes in size, and tumors that can be consequences of chronic infection or liver disease caused by hepatitis of any type.

• Abdominal ultrasound: This test can evaluate abnormalities in the liver and abdomen, and may also detect the fluid build-up in the abdomen, which can occur with liver failure. 
• Computerized axial tomography (CT): An abdominal CT scan can detect changes in the size and density of the liver and may visualize masses or signs of early cancer (a potential complication of hepatitis).
• Magnetic resonance imaging (MRI): An MRI can pick up on abnormalities that suggest liver dysfunction or cancer. 

A liver biopsy is a section of tissue taken from the organ and evaluated under a microscope to look for identifying features disease.

The most common type of liver biopsy is called a percutaneous biopsy, which involves inserting a hollow needle through the abdomen into the liver through which a sample of tissue can be extracted.

This is an outpatient procedure, which means it doesn't require a hospital stay. Usually, only local anesthesia is necessary (to numb the area into which the needle will be inserted). However, a sedative can be used if needed.

Because the symptoms of hepatitis can be mild or mimic other diseases—if there are any symptoms at all—it can be tricky to diagnose. If you have any symptoms that you think might point to a liver problem—especially jaundice—see your doctor. A simple blood test may be all that's necessary to determine if you have hepatitis and if you should be treated.