Difference between IgG and IgM antibodies.

Antibodies are a special type of proteins called immunoglobulins (international name - Ig). They are divided into five classes and are designated by Latin letters (IgM, IgG, IgA, IgE, IgD). Each class of antibodies belongs to a different stage and dynamics of the disease, which is an important factor in the diagnosis and treatment of various diseases. Taking into account these factors, the doctor can predict the risks, prescribe diagnostic tests and carry out treatment.


Number IgM antibodies can increase from the onset of the disease and reaches its peak by about the end of 1-4 weeks, depending on the nature of the infection, and then begins to decline over several months. With some infections, the duration of the presence of large amounts of IgM antibodies may increase. In such cases, an analysis of the avidity of these antibodies is prescribed. The rapid appearance of antibodies of the IgM class most often indicates the onset of an acute illness.

IgG antibodies appear in the body a little later (about two weeks after the onset of the disease), their levels increase more slowly than in the case of IgM, and their gradual decrease also occurs much more slowly (with some infections, they can generally persist throughout life). An increase in IgG antibodies indicates that the person is already familiar with this infection.


The analysis for the avidity of antibodies is carried out before planning pregnancy, as well as in some diseases to exclude infection. Avidity is the determination of the strength of the bonds between antigen and antibody.

Low-avidity antibodies are most often observed during initial infection with infection, high-avidity antibodies appear in the case of past infection or reinfection.

Conclusions TheDifference.ru

  1. Antibodies IgG and IgM belong to a different class of immunoglobulins and are responsible for the presence of infection in the human body. Their various indicators together show the specific stage and severity of the process.
  2. An increase in the body of antibodies of the IgM class indicates the onset of an acute illness. An increase in IgG antibodies in the body indicates that this infection is already familiar to him.