CD34+ cells may be isolated from blood samples using immunomagnetic or immunofluorescent methods.Antibodies are used to quantify and purify hematopoietic progenitor stem cells for research and for clinical bone marrow transplantation. However, counting CD34+ mononuclear cells may overestimate myeloid blasts in bone marrow smears due to hematogones (B lymphocyte precursors) and CD34+ megakaryocytes.Cells observed as CD34+ and CD38- are of an undifferentiated, primitive form; i.e. they are pluripotential hemopoietic stem cells. Thus, because of their CD34+ expression, such undifferentiated cells can be sorted out.