Enhanced yield platelet collection systems and methods

A chamber for use in a rotating field to separate whole blood into red blood cells and a plasma constituent carrying platelets comprising

• wall means defining first end second spaced apart walls for forming a chamber having a first region and a second region spaced from the first region, the first wall being oriented, in use, closer to the rotational axis than the second wall,
• means defining an inlet in the first region for directing whole blood into the first region of the chamber for separation into a first zone of red blood cells along the second wall and a second zone of plasma constituent along the first wall, means defining a first outlet in the second region of the chamber for conveying separated red blood cells the first zone, and
• means defining a second outlet for conveying the plasma constituent from the second zone at least in part while whole blood is directed through the inlet into the first region, the second outlet being located closer to the first region of the chamber than to the second region of the chamber.

A device for separating a suspension of plasma end platelets from whole blood comprising

• wall means defining a separation chamber operable for rotation about an axis to create within the chamber a low-G wall radially close to the axis and a high-G wall spaced radially further from the axis than the low-G wall,
• inlet means for introducing whole blood into a first region of the chamber during its rotation to initiate separation of red blood cells within the first chamber region toward the high-G wall and create a flow of plasma that moves within the first chamber region radially toward the low-G wall and elutes platelets into suspension, and
• first collection means for directing the radial flow of plasma and eluted platelets in the first chamber region to a first port in the first chamber region for transport from the chamber at least in part while whole blood is introduced by the inlet means into the first chamber region.

A chamber for use in a rotating field to separate whole blood into red blood cells and a plasma constituent carrying platelets comprising

• wall means for defining first and second spaced apart walls forming a separation zone having, in use, a low-G side located closer to the rotational axis than the other, high-G side, the separation zone forms a blood flow path that includes an entry region where whole blood enters the separation chamber to begin separation and a terminal region spaced from the entry region where separation is halted,
• means for conveying whole blood through the blood flow path from the entry region toward the terminal region to successively increase the surface hematocrit along the flow path by separating red blood cells toward the high-G side and the plasma constituent toward the low-G side, and
• means defining e first port in the entry region for collecting, at least in part while whole blood enters the entry region, the plasma constituent from the low-G side of the separation zone in the entry region where the surface hematocrit along the flow path is the least.

A method for separating a suspension of plasma and platelets from whole blood comprising the steps of

• rotating a chamber about an axis to create within the chamber a low-G zone radially close to the axis and a high-G zone spaced radially further from the axis than the low-G zone,
• introducing whole blood into an inlet region of the chamber to initiate separation of red blood cells toward the high-G zone of the inlet region, thereby creating a flow of plasma that moves radially toward the low-G zone of the inlet region end elutes platelets into suspension with it, and
• directing the radial flow of plasma and eluted platelets within the inlet region to a port in the inlet region for transport out of the chamber at least in part while whole blood is introduced into, the inlet region.

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

• rotating a chamber about an axis to create within the chamber a low-G zone radially close to the axis end a high-G zone spaced radially further from the axis than the low-G zone, the chamber forming a blood flow path that includes an entry region where whole blood enters the chamber to begin separation and a terminal region spaced from the entry region where separation is halted,
• conveying whole blood through the blood flow path from the entry region toward the terminal region to successively increase the surface hematocrit along the flow path by separating red blood cells toward the high-G zone and the plasma constituent toward the low-G zone, end
• collecting through a port in the entry region, at least in part while Whole blood enters the entry region, the plasma constituent from the low-G zone of the flow path in the entry region where surface hematocrit along the flow path is the least.