Red blood cell separation method

A method for centrifugally separating whole blood into red blood cells and a plasma constituent comprising the steps of

• rotating a separation zone about a rotational axis, the rotating separation zone having radially spaced apart walls with a high-G side and a low-G side located closer to the rotational axis than the high-G side, a blood flow path that extends circumferentially about the rotation axis, the first rotating separation zone including an entry region where whole blood enters the first rotating separation zone to begin separation and a terminal wall that is circumferentially spaced from the entry region, where separation is halted,
• directing whole blood into the rotating separation zone through a first path adjacent the entry region, to begin separation of the whole blood into red blood cells toward the high-G side and plasma constituent toward the low-G side,
• directing red blood cells separated in the first separation zone in a circumferential flow direction toward the terminal wall, and
• directing separated red blood cells from the rotating separation zone through a second path adjacent the terminal wall, the second path including a portion that is recessed into the high-G wall.