Antigens are substances that can be recognized and attacked by the body’s immune cells and that the body needs to remove. The main chemical component of most antigens is protein. Antibodies are proteins produced by immune cells that can bind to an antigen after the antigen is recognized by the body’s immune cells. Antibodies bind to antigens with specificity and specificity. There are at least four antigen antibody systems for hepatitis B virus: HBsAg/anti-HBs, HBeAg/anti-HBe, HBcAg/anti-HBc, and HBxAg/anti-HBx, which are called hepatitis B surface antigen/surface antibody, e antigen/e antibody, core antigen/core antibody, and x antigen/x antibody systems, respectively; among them, HBcAg is not HBcAg is not routinely tested because of the complicated testing process; x antigen/x antibody is not routinely tested because of its low level. There are five hepatitis B antigens and antibodies that are routinely tested: HBsAg/anti-HBs, HBeAg/anti-HBe, and anti-HBc, commonly known as “two and a half”. Whether it is self-limited or persistent hepatitis B, there is a specific pattern of evolution of serum “two-and-a-half” from hepatitis B virus infection to hepatitis B virus clearance by human body, or from disease onset to disease recovery, which is expressed as different combinations of the components of “two-and-a-half”. The pattern of serum hepatitis B virus markers is called “self-limiting”. The term “self-limiting” can be interpreted as self-recovery, while “persistent” can be interpreted as non-self-recovery and long-term recurrent attacks. After hepatitis B virus infection, the earliest antigen to appear is HBsAg, and the latest antigen to disappear is also HBsAg, which can be called “early out, late in”; HBeAg appears soon after the appearance of HBsAg, but disappears earlier than HBsAg, which can be called “late in, early out “In other words, the earliest antibody produced is anti-HBc, but it disappears very late; anti-HBe appears after the disappearance of HBeAg and before the disappearance of HBsAg; anti-HBs appears after the disappearance of HBsAg, and still exists for a period of time after the virus is completely removed from the liver cells , which lasts the longest time. Therefore, there are eight serum hepatitis B virus marker patterns from the time the hepatitis B virus infects the body to the time the body clears the hepatitis B virus: first, a single positive HBsAg, followed by sequential experiences of [HBsAg, HBeAg, anti-HBc] positivity, [HBsAg, anti-HBc] positivity, [HBsAg, anti-HBe, anti-HBc] positivity, [anti HBe, anti-HBc] positive, [anti-HBs, anti-HBe, anti-HBc] positive, [anti-HBs, anti-HBc] positive, [anti-HBs, anti-HBc] positive, and finally single anti-HBs positive; where [HBsAg, HBeAg, anti-HBc] positive, [HBsAg, anti-HBe, anti-HBc] positive, [HBsAg, anti-HBe, anti-HBc] positive, [anti HBe, anti-HBc] positive, [anti-HBs, anti-HBe, anti-HBc] positive, [anti-HBs, anti-HBc] positive, [anti-HBs, anti-HBc] positive can be referred to as “major triplet”, “major doublet”, ” Small triple-positive”, “small second-positive”, “resumed triple-positive”, “resumed second-positive”. From “major third-positive” to “major second-positive”, “major second-positive” to “minor third-positive”, “minor third-positive” to “minor third-positive”, “minor third-positive” to “minor third-positive”. From “minor third-positive” to “minor second-positive” indicates that the virus is still present in the liver cells from the time of infection and onset to the time of recovery, but the number of virus decreases in order; from “recovery third-positive” to “recovery second-positive” indicates that the virus is still present in the liver cells from the time of infection and onset to the time of recovery. From “recovery 3 positive” to “recovery 2 positive” indicates that the disease tends to terminate and enter the recovery phase, only residual virus exists in the liver cells, and the residual virus is getting less and less. In most acute hepatitis B, the evolution of the serum hepatitis B virus marker pattern from “major triple-positive” to “minor triple-positive” takes less than 3 months and is called self-limiting hepatitis B. Only in a small number of cases of acute hepatitis B, the serum hepatitis B virus marker pattern does not show a “small two-positive” pattern within 3 months, suggesting that it is likely to evolve into persistent hepatitis B. Under natural conditions, about half of the patients with persistent hepatitis B have a serum hepatitis B virus marker pattern that evolves to “minor triplet” during their lifetime. For those patients with persistent hepatitis B who are able to evolve from “major triplet” to “minor triplet”, the transition from “major triplet” to “minor triplet” usually occurs at the age of 35. “The age of transition is usually around 35 years. Only a minority of patients with persistent hepatitis B have a serum hepatitis B virus marker pattern that evolves to “revert to triple-positive” during their lifetime. For those patients with persistent hepatitis B who are able to evolve from “minor triplet” to “resuming triplet”, the age of transition from “minor triplet” to “resuming triplet” is usually 55 years. “The age of transition is usually around 55 years. It should be emphasized that a single positive HBsAg cannot be called a “healthy” carrier because although the infected person has no symptoms, the virus has already entered the liver; only a single positive anti-HBs indicates that there is no residual virus in the liver cells, but it does not mean that one will never be infected with hepatitis B virus again because anti-HBs is not permanently protective.