Bone marrow enrichment technique for detection and characterization of scarce abnormal cells

A frequent problem encountered in analysis of bone marrow aspirates is the small number of suspect cells in the material. We present a method for concentration of the cells in bone marrow aspirates which yields smears suitable for immunocytochemical techniques. Bone marrow sampling is performed in two steps: a first aspirate is used to prepare conventional smears and a second aspirate is submitted to two-step centrifugation to separate and collect the nucleated cells without use of a separation medium. Sufficient material is obtained to prepare a large number of films, thus allowing immunocytochemical investigation with a wide panel of monoclonal antibodies. The proportions of the different cell types are similar to those observed in conventional smears and cell morphology is unaltered. This enrichment procedure improves the accuracy of routine cytological bone marrow examination, may be easily applied in laboratories performing bone marrow studies and in our hands has proved of value for the detection and characterization of both malignant blood diseases and bone marrow dissemination of carcinoma.