IgM indicates that the body has recently been infected with the novel coronavirus, which is a sign of early infection, while IgG indicates that the body has developed a certain level of resistance to the virus. IgG is an immunoglobulin produced by the human immune system and is the main antibody produced by the human body in response to another immune response. It has a high affinity and is widely distributed in the body, and is the body’s “main antibody” to fight infections, and a positive IgG antibody to the new coronavirus indicates that the body has a certain degree of immunity to the new coronavirus. IgM is also a kind of immunoglobulin secreted by the human immune system, but it is the earliest antibody to appear in the initial humoral immune response, and is the “vanguard” of the body’s specific anti-infective force. When the new coronavirus-specific IgM antibody is detected in the serum of the human body, it suggests that the human body has recently been infected with the new coronavirus, and can be used as a diagnostic basis for early infection. It can be used as a diagnostic basis for early infection. In general, the IgM concentration is relatively low, short maintenance time and low affinity, while the IgG affinity is high and long maintenance time, and the two functions are independent of each other and interconnected.