A biological fluid separation system for a blood sample is disclosed. The biological fluid separation system includes a biological fluid collection device adapted to receive a blood sample and a centrifuge. The centrifuge is adapted to receive the biological fluid collection device such that with the biological fluid collection device received within the centrifuge and a rotational force applied to the biological fluid collection device, a plasma portion of the blood sample is separated from a cellular portion of the blood sample. The biological fluid collection device is only receivable within the centrifuge in one orientation.