In this 3-day course the basic principles of the protein microarray will be addressed by a combination of lectures, demonstration and hands-on training. The protein microarray technique can be used for HA antibody profiling for group level assessment of exposures to influenza viruses in small sample volumes from humans and animals (birds, horses, pigs, bats, carnivores a.o.). The training encompasses wet lab training but also the analysis and interpretation of assay results. Special attention will be given to specific issues of Influenza and flavivirus cross reactivity.