ABSTRACT
One of the major advances in laboratory medicine has been the ability to immunologically identify specifi c subsets of leukocytes and other cells by their expression of proteins and other markers. This process, termed “immunophenotyping,” employs monoclonal antibodies reactive against cell-associated determinants to distinguish specifi c subsets within a heterogeneous mixture of cells. Quantifi cation of a subset of interest can be readily accomplished by the use of a fl ow cytometer, an instrument
that electronically measures the intensity of scattered or emitted light from individual cells as they pass before a laser.
