Some donors can be recalled for your experiments; however, there are donors who are either not eligible for recall or are simply not interested in providing future donations. If recallable donors are desired, please specify this to your regional sales representative prior to placing an order to increase the likelihood that the recall will be successful. Timelines for donor recalls are as follows: Bone Marrow: eligible 35 days after last donation Leukopak: eligible 35-56 days after last donation Whole Blood: eligible 56 days after last donation Mobilized PB Leukopak: eligible 6 months after last donation for a leukopak or whole blood. Not recallable for another mobilized collection (lifetime limit of 1 donation).