Flow cytometry

5 mL blood or 2 mL bone marrow aspirate in lithium heparin, ACD or EDTA.

Fresh, unfixed lymphoid or other tissue in sterile tissue culture medium. 

Cell suspension labelled with fluorescent-conjugated antibodies and analysed on a flow cytometer.

Consult pathologist.

Assessment of lymphoid cell subsets especially CD4 numbers in patients with HIV infection;

classification of acute and chronic leukaemias and lymphomas;

occasionally required to distinguish reactive and neoplastic lymphocytosis;

detection of minimal residual disease / after fetomaternal haemorrhage add diagnosis of hereditary spherocytosis.

May also be used to count reticulocytes;

to detect platelet antibodies, to detect cell sub-populations (eg, red cell, leucocyte and platelet sub-populations in PNH), fetal red cells after fetomaternal haemorrhage;

to identify HLA-B27 phenotype;

to determine DNA ploidy and cell cycle characteristics; and

to enumerate stem cell numbers prior to peripheral blood progenitor cell collection for transplantation.

Positive staining indicates expression of the relevant antigen.

Report will identify and quantitate cell types present with an interpretative comment from the pathologist.

See also Cell immunotyping, DNA ploidy, Lymphocyte immunophenotyping and Kleihauer.