Two-four-five positivity is the second item inside the five items of hepatitis B, which is positive for hepatitis B surface antibody, the fourth item, which is positive for E antibody, and the fifth item, which is positive for hepatitis B core antibody. Two, four, five positives are seen in the following two cases: first, the old hepatitis B vaccine was injected, which should normally produce only the second positive, and occasionally produce two, four, two, five, two, four, five positives, where the second, or hepatitis B surface antibody positive can play a protective role, so that people are not easily infected with hepatitis B, and the fourth and fifth positives have no protective effect. This old-fashioned vaccine has been eliminated, and the existing vaccine prepared by recombinant yeast method will not produce four or five positives. Second, once infected with hepatitis B has recovered on its own, most of them will produce the second positive item after recovering on their own, and occasionally they will produce the second four, two five, two four five positive.