1, HBsAg and anti-HBs: adults infected with HBV, the earliest 1-2W, the latest 11-12W HBsAg first appeared in the blood. acute self-limiting HBV infection in blood HBsAg persists for 1-6W, asymptomatic carriers and chronic patients HBsAg can persist for many years or even for life. HBsAg itself is only antigenic, non-infectious. Anti-HBs is a protective antibody that begins to appear in the late stages of acute infection, some time after HBsAg has become negative, and gradually rises to a peak in 6-12 months, with a gradual decline in titer. Positive anti-HBs indicates immunity to HBV, which is seen in the recovery period of hepatitis B, previous infection and after hepatitis B vaccination. 2.PreS1 and anti-PreS1: PreS1 appears in the blood immediately after HBsAg in the early stage of infection, and turns negative quickly in the acute stage, suggesting that the virus is cleared and the condition improves. PreS1 positivity is a sign of HBV presence and replication, and persistent PreS1 positivity suggests chronicity of the infection. Anti-PreS1 is considered to be a protective antibody, which appears early in the infection. 3.PreS2 and anti-PreS2: PreS2 can be used as an indicator of HBV replication. Anti-PreS2 appears in the early stage of recovery from acute hepatitis and plays the role of protective antibody, and anti-PreS2 can also be used as an indicator of the immunization effect of hepatitis B vaccine. 4, HBcAg and anti-HBc: HBcAg in blood mainly exists in the core of Dane particles; HBcAg in liver tissue mainly exists in the nucleus of infected hepatocytes. HBcAg is highly immunogenic, and anti-HBc can be detected in almost all HBV-infected patients, unless there is a very rare mutation in the HBV C gene sequence or the infected person is immunodeficient. Anti-HBc-IgM is an antibody that appears earlier after HBV infection, the vast majority appear in the 1st W after the onset of the disease, and most disappear within 6 months, and anti-HBc-IgM positivity suggests an acute phase or an acute exacerbation of chronic hepatitis. 5, HBeAg and anti-HBe: HBeAg is a soluble protein, usually seen only in HBsAg positive serum. In acute HBV infection, HBeAg appears slightly later than HBsAg, and disappears after the extreme phase of the lesion, and if HBeAg persists, it predicts a tendency toward chronicity. In chronic HBV infection HBeAg is an important immune tolerance factor, and in most cases its presence indicates a period of high infection and low response. The disappearance of HBeAg and the production of anti-HBe is called seroconversion. The process of seroconversion implies a shift from immune tolerance to immune activation, which is often accompanied by an intensification of lesion activity. Anti-HBe positive conversion, HBV replication is mostly in a quiescent state, the infectiousness is reduced. HBV-DNA: HBV-DNA in the blood mainly exists in the Dane particles, HBV-DNA is a direct sign of viral replication and infectiousness. Regular testing of HBV-DNA is important for determining the degree of viral replication, the size of infectiousness, and the efficacy of antiviral drugs.