Expression strength key

Expression strength effectively reflects how strongly a molecule is expressed by neoplastic cells based on the intensity of the observed fluorescence.

It can be helpful in flow cytometric diagnosis: e.g. the characteristically weak expression of CD79b by CLL cells, or the characteristically strong expression of CD25 by the cells of HCL

It is however associated with some difficulties since antibodies and fluorochromes can differ between laboratories and the judgment is often subjective based on the compartor used. However, as the concept is useful we provide a general statement on expected fluorescence intensity that can be expected for each disorder; it is important to be aware of the lab-lab variability and assessment when used for interpretation.