Immunophenotyping is a technique used to study the protein expressed by cells. This technique is commonly used in basic science research and laboratory diagnostic purpose. This can be done on tissue section (fresh or fixed tissue), cell suspension, etc. An example is the detection of
tumor marker, such as in the
diagnosis of
leukemia. It involves the labelling of
white blood cells with
antibodies directed against surface
proteins on their membrane. By choosing appropriate antibodies, the differentiation of
leukemic cells can be accurately determined. The labelled cells are processed in a
flow cytometer, a laser-based instrument capable of analyzing thousands of cells per second. The whole procedure can be performed on cells from the
blood,
bone marrow or
spinal fluid in a matter of a few hours.