Hepatitis is a group of infectious diseases caused by infection with the hepatitis virus. Viral hepatitis B is one of these diseases and is referred to as “hepatitis B” for short. The virus that causes hepatitis B is called the hepatitis B virus. Hepatitis B viruses enter the human bloodstream, where they grow and multiply. The way they reproduce is by “replicating” inside the body. As the name suggests, “replication” is the process of creating a new virus in the same way as the original virus. Of course, this process is very complicated. Since the hepatitis B virus is present in the blood, doctors can detect it through laboratory tests. The test is done by drawing a small amount of blood from a vein in the patient’s forearm, separating the serum, and then checking the serum for any “traces” of the hepatitis B virus. There are five general tests for hepatitis B, also known as the Hepatitis B Five Markers (HBV-M), or “two halves”. The results of the “two halves” test are indicated by plus or minus signs (i.e., + and -). (+) means positive; (-) means negative. These five tests are: 1) surface antigen (abbreviated as HBsAg); 2) surface antibody (abbreviated as anti-HBs); 3) e antigen (abbreviated as HBeAg); 4) e antibody (abbreviated as anti-Be); and 5) core antibody (abbreviated as anti-HBc). Here we introduce these tests one by one. 1, surface antigen (HBsAg): surface antigen is often referred to in the past as the “Australian antibody”. “AusAg” is short for “Australian antigen”, because it was first found in Australia, so it is called “AusAg”. Hepatitis B virus has a very simple structure, but it also has a shell. This shell is a protein called “surface antigen”. Its presence signals the presence of the hepatitis B virus. Therefore, if the test is positive for “surface antigen”, it means that the body is infected with hepatitis B virus. 2. Surface antibody (anti-HBs): When hepatitis B virus invades the body, the body will produce substances to resist it. This substance is also a kind of protein, which is called “antibody”. Antibodies have the ability to protect the human body. When the body produces “surface antibodies”, it means that the body is resistant to the hepatitis B virus. Nowadays, many people have been vaccinated against hepatitis B, so their bodies will also produce “surface antibodies”, and the test for “surface antibodies” will also be positive. At this time, you hope that the “surface antibody” should be positive, which signifies that the hepatitis B vaccine you have injected has been successful, and you will not be infected with hepatitis B again. 3.e antigen (HBeAg): e antigen is the sign of hepatitis B virus replication. It can determine the size of infectiousness. If the test is positive for e antigen, it means that the hepatitis B virus is actively replicating in the body, and the amount of poison in the blood is large and highly infectious. Therefore, e antigen positive is definitely not a good thing. 4. e antibody (anti-HBe): e antibody is found in the examination, which indicates that hepatitis B is relatively better and brings good news to the patient. Because its positivity signifies that the replication of hepatitis B virus has changed from active to relatively quiescent, the amount of virus in the blood is reduced, and the infectiousness is also relatively reduced. 5, core antibody (anti-HBc): core antibody is the earliest kind of antibody that appears after the human body is infected with hepatitis B virus. However, it has no protective effect on human body. When it is positive, if there are a lot of plus signs (the medical term is “high titer”), it suggests that the virus is replicating and is highly infectious. If you were strongly positive in the past and are now positive, but with fewer plus signs, you have had “Hepatitis B” before, and this positivity can last for years or decades. The above is only simple knowledge, the actual doctor in the laboratory results to determine the patient’s condition, to integrate many factors, such as epidemiological history, clinical symptoms and other laboratory results, and not rely on one or two test results to make a conclusion.