Sandwich ELISA is the most frequently used immunoassay format for the detection of high molecular-weight antigens (e.g. proteins and peptides). An antibody pair of the immobilized capture antibody and detection HRP-labelled antibody in solution forms a “sandwich“ with a target antigen in between. The use of an HRP-labelled detection antibody for detection allows optimal assay sensitivity at short assay time in human blood samples such as serum or EDTA, heparin or citrate plasma.