Immunophenotyping
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. An example of information provided through Immunophenotyping: "The flow cytometric immunophenotyping report indicated the malignant cells were positive for CD19, CD10, dimCD20, CD45, HLA-DR, and λ immunoglobulin light chain. There was no coexpression of CD5 or CD23 by the monoclonal B-cell population." Immunophenotyping is a very common flow cytometry test in which fluorophore-conjugated antibodies are used as probes for staining target cells with high avidity and affinity. This  technique allows rapid and easy phenotyping of each cell line in a heterogeneous sample according to the presence or absence of a protein combination. Thus, visibility increases in complex samples.