Colloidal gold is gold particles suspended in aqueous solution in colloidal state with particle size below micron. It is a kind of non radioactive tracer commonly used in immunolabeling technology. Colloidal gold reagent is a medicinal reagent, also known as colloidal gold test paper, which takes colloidal gold as the color medium and uses the principle of specific binding of antigen and antibody in immunology.

Colloidal fitting reagent has the advantages of convenience, specificity, sensitivity, strong stability, no need for special equipment and intuitive result judgment. Therefore, it is especially suitable for grass-roots inspectors, mass testing and large-area general survey. It has great development potential and broad application prospects. The colloidal gold in the colloidal gold reagent "dyes" the antibody with gold to form a gold labeled antibody. In this way, the antibody that could not be seen by the naked eye can be seen by us because of its color.

Colloidal gold test paper fixes colloidal gold on PVC test paper, leaves sample adding holes, and sets up detection line and quality control line, so that users who want to test can easily use colloidal gold test paper for testing.

Generally speaking, the test process of colloidal gold test paper is as follows: first drop the test sample on the sample adding hole, and then add a few drops of liquid medium to let the liquid flow to the water absorbing pad at the other end of the test paper. In this process, the test paper will be chromatographed. If there is a specific virus antigen in the sample, it will be recognized by the gold standard antibody on the binding pad, The antigen antibody complex is formed, and the color bands that can be recognized by the naked eye appear, so that the test results can be known at a glance.