Acute HBV Infection
Initial infection with hepatitis B virus. May result in liver failure and sometimes death, but over 90% of adult cases will recover completely and develop immunity. 

AFP
Alpha-fetoprotein is a biomarker for liver cancer. Elevated or rising AFP levels can indicate liver cancer.

ALT
Alanine transaminase (or alanine aminotransferase). Elevated ALT levels can indicate active liver damage. Also referred to as SGPT (serum glutamate pyruvate transaminase).

AST
Aspartate transaminase (or aspartate aminotransferase). Elevated AST levels can indicate active liver damage, but it's less specific than ALT. AST may also be elevated with heart and skeletal muscle damage.
Also referred to as SGOT (serum glutamic-oxaloacetic transaminase).

Anti-HBc
Hepatitis B core antibody. A negative HBsAg but a positive total anti-HBc test indicates past HBV infection.
A positive IgM anti-HBc test indicates the person has acute hepatitis B and has only been recently infected
(< 6 months) with HBV. Not a protective antibody.

Anti-HBe
Hepatitis B e antibody. Generally indicates low viral replication and infectivity. Not a protective antibody.

Anti-HBs or HBsAb
Hepatitis B surface antibody. Levels ≥10 mIU/mL indicate protection against HBV.

Chronic HBV Infection
Clinical term used to describe lifelong HBV infection, indicated by presence of hepatitis B surface antigen (HBsAg) in the blood for more than six months.

Cirrhosis
Severe scarring of the liver that can lead to liver failure and death. Common causes include chronic hepatitis B or C, excessive alcohol consumption, and nonalcoholic fatty liver disease.

HBeAg
Recommended baseline test after initial diagnosis of chronic HBV infection. HBeAg is a marker of high viral replication and infectivity (though some mutant HBV strains have increased viral replication but negative HBeAg). 

HBeAg Seroconversion
Loss of HBeAg and development of anti-HBe, is indicative of a favorable response to HBV treatment. It can also occur spontaneously in the course of chronic HBV infection.

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HBIG

Hepatitis B immune globulin. Provides short-term protection against HBV infection and is given in combination with the 3-dose hepatitis B vaccine, especially to unprotected individuals exposed to HBV or newborns born to chronically infected mothers.

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HBsAg

Hepatitis B surface antigen. The gold standard test to diagnose chronic hepatitis B. Its presence for at least six months after initial infection indicates chronic HBV infection.

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HBV DNA

Hepatitis B virus deoxyribonucleic acid. The basis of the most direct blood test used to measure the hepatitis B viral load. It is used to assess and monitor the treatment of chronic HBV patients.

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Hepatitis

General term meaning “inflammation of the liver,” which can be caused by bacterial infections, trauma, adverse drug reactions, and a range of viruses including hepatitis A, B, C, D, and E.

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Hepatitis A

Disease of the liver caused by infection with the hepatitis A virus (HAV).  HAV is transmitted through food or water contaminated by fecal matter from humans infected with HAV. It is vaccine-preventable. HAV does not cause a chronic infection or liver cancer.

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Hepatitis B

Disease of the liver caused by infection with the hepatitis B virus (HBV). Chronic infection with HBV can lead to death caused by cirrhosis, liver failure, or liver cancer. It is vaccine-preventable.

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Hepatitis C

Disease of the liver caused by infection with the hepatitis C virus (HCV).  Largely a bloodborne infection. Chronic hepatitis C infection can also cause liver cancer and cirrhosis. Over 95% of patients with chronic hepatitis C infection are cured after a 2-3 months course of oral hepatitis C antiviral therapy. There is no vaccine to prevent HCV infection.

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Hepatitis D

Disease of the liver caused by the Hepatitis D or delta virus. Largely a bloodborne infection that can cause chronic infection, liver cirrhosis and liver failure. Hepatitis D only infects a person who is also infected with hepatitis B, hence the hepatitis B vaccine will also protect against hepatitis D.

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Hepatitis E

Disease of the liver caused by the hepatitis E virus. Like hepatitis A, it is transmitted by contaminated food or water in endemic regions of the world. Pregnant women who became infected can develop severe liver disease and liver failure. Chronic hepatitis E infection is rare but has occurred in immunocompromised persons and transplant recipients. There is only one hepatitis E vaccine and it is only approved in China.

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Hepatocellular Carcinoma (HCC)

Most common type of primary liver cancer. Worldwide, an estimated 80% of HCC is caused by chronic HBV or HCV infection. Other causes of HCC include alcoholic cirrhosis, non-alcoholic fatty liver disease associated with obesity, and aflatoxin, a heat resistant toxin produced by certain mold that have contaminated food crops including peanuts and cottonseed.