The Trastuzumab immunogenicity assay employs the bridging ELISA technique. A precoated 96 well capture antibody plate is provided. Quality control and test samples are pipetted into the appropriate wells. Anti-Trastuzumab present in biological matrices binds the immobilized capture antibody. After washing away any unbound substances, secondary antibody is added to the wells and after a final wash a detection reagent is added. The plate is washed to remove any unbound antibody-enzyme reagent and a substrate solution is added to the wells for color development. The color development is proportional to the amount of anti-Trastuzumab present in test samples. Four levels of QC samples give a qualitative reference signal which can be used to determine the level (High, Medium, Low, Negative) of anti-Trastuzumab antibody in the unknown samples. Range: 125ng/ml - 31.25ng/ml. Sample types: serum, plasma. Reactivity: human/mouse/rat.