Abstract: A simple in vivo bioassay suitable for the routine quality control testing of a new erythropoiesis stimulating protein was developed. Subcutaneous administration of the new erythropoiesis stimulating protein to Balb/c mice in a single dose resulted in a dose-dependent increase in the number of circulating reticulocytes. Within the erythropoiesis stimulating protein dose range of 3.125 to 200 ng per mouse, there is a strong linear relationship between the dose and reticulocyte counts in the treated mice. This linear relationship allows us to determine the biological potency of the testing erythropoiesis stimulating protein preparation relative to a reference standard using parallel line assay. Accuracy, precision, dose variation and blood collection time of this method were analyzed in order to choose doses in the linear range that are suitable for setting up a useful, precise, and economical bioassay.

Key words: Erythropoietin, Erythropoietin, Erythropoiesis stimulating protein, Erythropoiesis stimulating protein, Bioassay, Bioassay, Reticulocyte count, Reticulocyte count, Anemia, Anemia