Described is a method for controlling fluid volume balance. A controller is configured with a first set of inputs comprising a hematocrit, a total blood volume, and an ACD ratio. A maximum extracorporeal RBC amount during the procedure is estimated based on the first set of inputs. A fluid circuit is primed with a priming fluid. Whole blood is drawn from a blood source and separated into a RBC component, a target cell component, and a plasma component. The target cell component is directed to a product container. The product container comprising the target cell component is treated. A treated target cell component, a portion of the RBC component remaining in the fluid circuit, and/or a portion of the plasma component remaining in the fluid circuit are returned to the blood source. A first response action is provided if the maximum extracorporeal RBC amount estimated is above a programmed limit.

A method provided for determining a range for the amount of light-energy attenuating material that may be present in a suspension containing target cells (such as MNCs), light-energy attenuating matter (such as RBCs and plasma), and a light-energy activatable compound (such as psoralen) so that a desired therapeutic effect (such as the percentage of MNCs in which apoptosis occurs) is obtained when the suspension is subjected to a known amount of light energy. In a related aspect, a method is provided for preparing a suspension containing target cells, light-energy attenuating matter, and a light-energy activatable compound so that a desired therapeutic effect is obtained when the suspension is subjected to a known amount of light energy.

A method of collecting mononuclear cells, comprising separating whole blood into plasma and cellular components, combining the cellular components with plasma replacement fluid to form a first mixture, and separating the first mixture into mononuclear cells and at least one component.

Methods and systems for the treatment and post-treatment processing of a mononuclear cell product are disclosed. The methods and systems include and provide for the separation of excess conditioning fluid and unbound treating agent prior to return of said treated mononuclear cell product to a patient.

A peristaltic pump-based apparatus for capturing circulating tumor cells (CTCs) from blood is provided that includes a feedback control architecture that uses models of pump operation and measures of internal pressure fluctuations of the pump (e.g., in the form time-varying and/or position-dependent pressure oscillation data) to adjust pump operating characteristics that smooth pump operation, thereby improving viscosity and consistency of fluid flowing through the pump to a connected microfluidic capture device.