Method introduction: Immunochromatography is a new type of immunoassay method that appeared in the early 1980s. It is a simple and rapid immunological detection technique established on the basis of immunofiltration. The principle is to fix the specific antibody on a certain zone of the nitrocellulose membrane first. When the dried nitrocellulose end is immersed in the sample (urine or serum), the sample will move forward along the membrane due to capillary action. Move, when moving to the area where the antibody is fixed, the corresponding antigen in the sample will specifically bind to the antibody. If stained with immunogold or immunoenzyme, the area can show a certain color, so as to achieve specific immunity. diagnosis.