System And Method For Collecting Plasma

What is this patent about?

’926 is related to the field of blood apheresis, specifically systems and methods for collecting plasma from a donor. Apheresis involves withdrawing blood, separating it into components, collecting the desired component (e.g., plasma), and returning the remaining components to the donor. Regulations limit the amount of blood components that can be removed, creating a need for precise collection methods.

The underlying idea behind ’926 is to accurately determine the pure plasma volume collected during apheresis by accounting for the anticoagulant mixed with the plasma. This is achieved by calculating the percentage of anticoagulant in the collected plasma based on the donor's hematocrit and the amount of anticoagulant introduced. By calculating the volume of pure plasma, the system can collect the maximum allowable plasma volume without exceeding regulatory limits.

The claims of ’926 focus on a method and system for collecting plasma that includes determining the donor's weight and hematocrit, calculating the volume of anticoagulant to be collected with the plasma, calculating a target volume of pure plasma based on the donor's weight, and determining a target collection volume based on the calculated volume of anticoagulant and the calculated volume of pure plasma. The system then withdraws blood, introduces anticoagulant, separates the blood, collects the plasma, and continues until the target collection volume is reached.

In practice, the system uses a blood component separation device , such as a centrifuge, to separate the blood into plasma and other components. Anticoagulant is introduced into the withdrawn blood at a predetermined ratio. The system monitors the amount of anticoagulant added, either by tracking pump rotations or measuring the weight change of the anticoagulant source. The donor's hematocrit is either pre-determined or measured during the process, potentially using an optical sensor to monitor red blood cell volume within the separation device.

This approach differs from prior art systems that simply collect a fixed total volume of plasma and anticoagulant. Because the percentage of anticoagulant in the collected mixture varies depending on the donor's hematocrit, prior systems could not consistently collect the maximum allowable volume of pure plasma. By calculating the pure plasma volume, ’926 enables the collection of a standardized volume of pure plasma from each donor, maximizing plasma yield while adhering to regulatory constraints.