Low lymphocytes do not necessarily mean AIDS, but there are many diseases that can cause low lymphocytes. For example, the common influenza virus can cause a drop in lymphocytes after infection, and the current new coronavirus can also cause a drop in lymphocytes after infection. After infection, HIV goes through a long incubation period before it enters the AIDS stage, causing a variety of symptoms. To check whether a patient is infected with AIDS, blood should be drawn to check for the presence of HIV antigens and antibodies in the patient’s body, and it is not possible to confirm the diagnosis by simple blood tests. If the patient is positive for antigens and antibodies, the patient is diagnosed with AIDS. Once a patient is diagnosed with AIDS, he or she should be treated with antiretroviral drugs as soon as possible to avoid progression to the AIDS stage.