HPLC analyses on day 14 after addition of SCF progressively later during the culture period.

EPO (4 U/mL) was present in the culture medium of all cultures and SCF (50 ng/mL) was added on the days indicated on the left in matched cultures. HPLC measurements performed on day 14 for all the samples. The HbF and HbA elution times were determined with standard proteins and by mass spectroscopy. The HbF/HbA ratio, expressed as a percentage, is shown on the right. The panels shown are representative of cultures from 3 separate blood donations demonstrating similar results.