Serum of slaughter pigs is being used for routine testing of antibodies against pathogens and can be used for detection of antibiotic residues. Since the assay formats differ (direct detection of antibodies vs. inhibition assays for residues), these tests are performed in parallel, not in a multiplex set-up. For this study, a protocol for testing both antibodies and residues in one sample was investigated using the deticated multiplex xMAP platform for Luminex.