The *Center for Biologics Evaluation and Research (CBER)* has received inquiries about the required 48-hour period between plasmapheresis procedures contained in 21 CFR 640.65(b)(4). Some investigators have interpreted the 48-hour period to be two days and some investigators have interpreted the requirement to be not less than 48 hours.
One recommendation coming from the ongoing Retrospective Review of Biologics Regulations is that the wording for this 48-hour period be changed to read two days. *CBER* agrees with this recommendation and is moving to change the wording in the regulations.
The required 48-hour period is two calendar days, regardless of the time of day that the donor is plasmapheresed.
*Material between asterisks is new or revised*