Due to its ability to analyze multiple parameters across different cell types within a sample, flow cytometry can provide very rich and clinically valuable data sets from even small volumes of blood. However, flow cytometry is a challenging platform to master, and requires significant investment into equipment and technical training. So, for many researchers, outsourcing flow cytometry to a Contract Research Organization (CROs) is both cost-effective and the best way to ensure the highest quality of data from their samples. So, what types of flow cytometry applications are the most outsourced to CROs?