To test the DiaCHIP under real-life conditions, we analysed the blood serum of a person that has been immunized against tetanus for the presence of anti-tetanus antibodies. First we confirmed the binding of antibodies present in the blood to our purified tetanus antigen by ELISA. Then we spotted the antigen and GFP, which both were expressed in E.coli and purified by His-tag affinity purification, on a PDITC surface. The much stronger binding of blood components to the tetanus antigen spots compared to GFP spots indicates specific interactions. By confirming that the bound blood components are human antibodies with anti-human, we successfully demonstrated that we are able to detect antibody binding even in complex samples