Method and system for collecting leukoreduced red blood cells

A method for collecting leukoreduced red blood cells employing a spinning membrane separator including a membrane configured to spin about a generally vertically-oriented axis within a housing, the housing including an upper end region and a lower end region in an operating position and the separator including a red blood cell outlet in the upper end region of the housing and a whole blood inlet in the lower end region of the housing, the method comprising:

• flowing additive solution from a first container into the whole blood inlet of the housing to prime the separator;
• flowing whole blood into the whole blood inlet of the housing;
• separating red blood cells from the whole blood;
• flowing separated red blood cells out of the red blood cell outlet of the housing through a red blood cell flow path;
• combining the separated red blood cells with additive solution from the first container in the red blood cell flow path;
• passing the separated red blood cells and additive solution combination directly from the red blood cell flow path through a leukoreduction filter;
• and
• collecting the filtered red blood cells and additive solution in a second container.