Flow cytometry is a technique that scientists and researchers use to define the characteristics of cells or other microscopic particles. Working within a laboratory as a lab worker, you go through a test process that involves putting a population of cells into liquid. You then put these prepared samples in an instrument called a flow cytometer. In addition to defining physical and chemical characteristics, this process can help count cells, sort cells, detect microorganisms or proteins, or test for specific conditions, such as blood cancers. Cytometry lab workers use computers to record results and produce documentation for research or clinical work.