Microarrays have the potential to become the next generation blood-testing platform. This commentary covers various aspects of such development presented in part at the Scotblood 2006 Meeting. Current mandatory testing includes antibody and antigen determination in both blood grouping and microbiology testing. While antibody determination is limited to phenotypic assays, antigen detection can be accomplished by genotyping or phenotyping. Applicability of various types of assays to microarrays, precision and sensitivity levels and correlation between genotyping and phenotyping results are briefly discussed and some of the main questions that need to be answered highlighted in future trends.