Influence of peripheral blood admixture on the number of hematopoietic progenitor cells (CFU-GM and BFU-E) in human bone marrow aspirates

Peripheral blood contamination in human bone marrow aspirates was calculated from the ratios between the erythrocyte and nucleated cell counts in both the bone marrow aspirate and a simultaneously obtained peripheral blood sample. This method is based upon experimental data which showed that the erythrocytes in bone marrow aspirates are mainly derived from the intravascular blood compartment. A strong negative correlation was found between the peripheral nucleated cell fraction (FBl) and the number of myeloid progenitor cells in 65 bone marrow samples (correlation coefficient r = -0.51; p less than 0.001). A similar correlation was found between erythroid progenitor cells and peripheral blood fraction (r = -0.55; p less than 0.01). The culture conditions were continuously monitored, using large batches of frozen marrow samples as controls. The correction for peripheral blood admixture permits a more reliable and reproducible interpretation of the quantitative results obtained from studies on the number of clonogenic cells in human bone marrow aspirates. Moreover, the method allows the interpretation of data obtained from bone marrow samples which are heavily contaminated by peripheral blood.