A blood centrifuge, comprising: means for containing a blood sample during rotation to separate the blood sample into component-rich regions comprising components of differing densities, the containing means having a center rotation axis； and means for accepting an input rotation rate and translating the input rotation rate into an output rotation rate, the accepting and translating means being rigidly connected to the containing means to drive the containing means to rotate about the center rotation axis at the output rotation rate, and wherein the output rotation rate is about twice the input rotation rate.
