The immune complex test is a test designed to evaluate the status or proper functioning of the immune system. The criterion used to evaluate the operation of the immune system is via the presence of so-called immune complexes.

An immune complex is an association formed between large numbers of antigens and the corresponding antibodies. The latter are produced in a specific response to the presence of the antigen, which has been perceived as being foreign by the body's immune system. The individual antigen-antibody complexes can associate together to form the interlocking network that represents an immune complex.

Normally, immune complexes are removed from the bloodstream by specialized cells of the spleen called macrophages and by other specialized cells located in the liver. However, if this clearance does not occur, the immune complexes will continue to circulate, and will become trapped in the kidneys, lung...