The present invention relates to a multiple bag system for fractionating blood, said system comprising a fluid collecting bag (B.00) comprising at least one outlet port; at least first and second sampling bags (B.10, B.12), each comprising at least one inlet port and at least one outlet port; and means for transferring fluid from the fluid collecting bag (B.00) to the sampling bags (B.10, B.12); wherein the means for transferring fluid comprises an acoustic sorter (AS0). The present invention also relates to a method for fractionating blood into blood products.