Cloning efficiency of normal PB (NPB; n = 6), G-CSF-mobilized PB (n = 4) and IM PB (n = 7) CD34⁺ cells. The number of CFCs is the sum of the number of BFU-E (□)-, CFU-GM (▧)- and CFU-granulocyte erythrocyte monocyte macrophage (GEMM; ▪)-derived colonies cloned per 2000 CD34⁺ cells plated. Values are expressed as the mean ± SD. Difference in CFC formation between normal PB and IM PB was statistically significant (P < .005).