Human dimeric erythropoietin has enhanced erythropoietic activity.

CD34⁺ cells were purified and grown in semisolid medium containing 0.1 to 0.6 U/mL (as determined by proliferation assay) hEpoM (black) or hEpoD (white). Experiments were performed in triplicate. Mean BFU-e numbers (A) and total erythroid cell numbers of individual experiments (B) are given.