The Human CD19 ELISA Pair Set is for the quantitative determination of Human CD19.The Sino Biological ELISA Pair Set is a solid phase sandwich ELISA (Enzyme-Linked Immunosorbent Assay). It utilizes a monoclonal antibody specific for Human CD19 coated on a 96-well plate. Standards and samples are added to the wells, and any Human CD19 present binds to the immobilized antibody. The wells are washed and a horseradish peroxidase conjugated mouse anti-Human CD19 monoclonal antibody is then added, producing an antibody-antigen-antibody sandwich. The wells are again washed and TMB substrate solution is loaded, which produces color in proportion to the amount of Human CD19 present in the sample. To end the enzyme reaction, the stop solution is added and absorbances of the microwell are read at 450 nm.