A method and apparatus for red blood collection and filtration is provided wherein a red blood cell collection assembly provides for leukoreduction filtration concurrent with or soon after the red blood cell separation and collection procedure. After red blood cells have been collected, an unwanted blood component, e.g., buffy coat, is diverted into the red blood cell collect line. Operation of a peristaltic pump engaging pump loop allows insertion of a pre-determined quantity of buffy coat into the collect line. The buffy coat can therefore push red blood cells out of the filter and into a collect bag without diluting the collected red blood cells. Alternatively, gravitational force may be used to allow the unwanted blood component to displace red blood cells out of the filter.
