Preparation of cells from blood

Peripheral blood is a bountiful source of numerous cell types that are easily analyzed by flow cytometry for a variety of properties. The monodisperse nature of blood makes preparation of these cells relatively easy if the coagulation cascade is inhibited. For some studies the presence of serum can be a confounding factor, although this is often overcome by merely pelleting the cells from the serum and washing the remaining cells several times. Blood, particularly from humans and primates, should be considered highly infectious whether or not from a healthy donor. Therefore universal precautions should be followed at all times. Techniques and route of collection may have a profound influence on the condition and nature of the blood being obtained. Performing venipuncture with an extremely small gauge needle may disrupt cells and prevent satisfactory analysis. Venous blood and arterial blood may yield differing data. Even blood collection at different times of day may yield diurnal variations in some assays. The demands of each cell type and of each assay dictate specific preparation, fixation, storage, and staining protocols. However, the overall goal for preparation of cells from blood, for all of the assays, remains the same--collect and prepare the cells in such a manner that they accurately represent the in vivo state.