Hepatitis B (HBV) - PreS1
The PreS1 antigen is located on the surface of Dane particles and tubular particles, exhibiting hydrophilicity and immunogenicity. Its peptide segment 21-47 is a key binding site for HBV to liver cells, which is crucial for HBV attachment and invasion of liver cells. The presence of PreS1 antigen in serum indicates the presence of HBV. It is only found in infectious HBV particles and is highly consistent with HBV-DNA and HBeAg tests, making it a useful supplementary test. PreS1 antigen testing helps assess the prognosis of hepatitis B and the efficacy of treatment, especially in HBeAg-negative patients, where high levels of PreS1 antigen may suggest the need for antiviral therapy.