Flow cytometry (FCM) is a multi-parameter, rapid quantitative technique for the analysis of individual cells or other biological particles at the cellular molecular level. FCM adopts an optical measurement method to count, identify and classify a single cell or other biological particle suspended in a flowing liquid. It can analyze tens of thousands of cells at high speed and measure multiple parameters from one cell at the same time. With the advantages of high speed, high precision and accuracy, FCM is recognized as one of the most advanced cell quantitative analysis techniques.