This experiment use double-sandwich elisa technique and the ELISA Kit provided is typical. The pre-coated antigen is Mouse APA antigen .Samples and antigen are added into ELISA plate wells and washed out with PBS or TBS. Then Avidin-peroxidase conjugates are added to ELISA wells in order; Use TMB substrate for coloring after reactant thoroughly washed out by PBS or TBS. TMB turns into blue in peroxidase catalytic and finally turns into yellow under the action of acid. The color depth and the tes