We compared relative efficacies of all 3 G-CSF/IgG-Fc fusion proteins to PEG-G-CSF in the single injection rat neutropenia study since this model most closely mimics how PEG-G-CSF is used in the clinic and provides the best test for relative potencies of the different fusion proteins to PEG-G-CSF. This evidence concerns the gene CSF3 and Decreased total neutrophil count.