Disposable fluid circuits and methods for cell washing

A method for the sterile sequential treatment of a biological fluid comprising:

• (a) obtaining a reusable cell processing apparatus comprising a separator element for receiving a separation device for effecting the separation of biological fluid into two or more fractions;
• (b) obtaining a first disposable fluid processing circuit comprising a separation device in fluid communication with a pre-attached first product container and an access device for sterile connection to a source of biological fluid;
• (c) mounting said first disposable fluid processing circuit onto said reusable cell processing apparatus;
• (d) sterilely joining a first source container of biological fluid to said first disposable fluid processing circuit;
• (e) introducing said biological fluid from said first source container into said separation device to separate a desired biological cell component from a remainder of said biological fluid;
• (f) collecting said separated biological fluid component in said first product container;
• (g) transferring said collected biological fluid of said first product container to a pre-attached separation chamber;
• (h) separating said collected biological fluid in said pre-attached separation chamber into first and second fractions;
• (i) decanting one of said fractions from said pre-attached separation chamber and introducing one of said fractions into a second source container;
• (j) removing said first disposable fluid processing circuit from said reusable cell processing apparatus;
• (k) obtaining a second disposable fluid processing circuit, comprising a separation device in fluid communication with a pre-attached second product container and an access device for sterile connection to said second source container;
• (l) mounting said second disposable fluid processing circuit onto said reusable cell processing apparatus;
• (m) introducing the contents of said second source container into said separation device of said second disposable fluid processing circuit to separate a desired biological fluid component from a remainder of said biological fluid;
• and
• (n) collecting a desired separated biological fluid fraction in said second product container of said second disposable fluid processing circuit.