Now that you have successfully obtained a custom antibody against your antigen, the final step is to use that antibody in your research assays. In this section, we first discuss how to properly store your antibody so that it can be used for years to come. Next, we provide a protocol for running a peptide blocking or inhibition study. This assay is critical for demonstrating antibody specificity against the target protein in assays such as Western Blot. In order to use the peptides properly, we also provide a protocol for re-solubilizing some of the peptide. Next we provide a protocol for running an ELISA with the antibody against your target. We also look at Western Blots in detail and provide specific recommendations for interpretation and troubleshooting of these results. Lastly, we provide a protocol for affinity purifying additional serum using affinity columns that we provide.