It is not advisable to donate blood if you are four or five positive for hepatitis B, because being four or five positive indicates that the person has previously been infected with the hepatitis B virus. Although it is possible that the hepatitis B virus has been cleared by the body, it is not possible to guarantee that the blood circulation does not contain any hepatitis B virus DNA simply by using this, although it is possible to detect very small amounts of hepatitis B virus DNA molecules using more accurate and sensitive means. But for these undetectable cases, it is not possible to completely exclude the possibility of the blood containing these hepatitis B viruses, so blood donation is also not recommended for hepatitis B IV and V positive cases. In clinical practice, if the hepatitis B five items in the four or five positive, that is, the hepatitis B core antibody and E antibody positive, there is a part of the check high sensitivity of the hepatitis B virus DNA, and even be able to check. Therefore, blood donation is not recommended in the case of four or five positive hepatitis B items.