Systems and methods are provided for collecting a platelet product from a fluid including platelets and plasma. Platelet-rich plasma is separated from at least a portion of another constituent of the fluid and then may be further separated into concentrated platelets and platelet-poor plasma, with the concentrated platelets being resuspended. Separated platelets (in the form of platelet-rich plasma or resuspended platelets) are conveyed through a size exclusion filter and into a platelet storage container. The size exclusion filter is configured to remove platelet clumps and/or particles larger than a platelet from the separated platelets. Subsequently, an additive is conveyed through the size exclusion filter and into the platelet storage container. Conveying additive through the size exclusion filter improves platelet recovery in the platelet product by displacement of separated platelets with the additive and may also break up any platelet clumps that are present in the size exclusion filter.
