Periodic alternating interface positioning to lower WBC contamination of apheresis platelet concentrates: a multicenter evaluation

BACKGROUND: A new software version of a cell separator (AS TEC 204, Freseni us) providing WBC-reduced single-donor plateletpheresis concentrates was te sted. STUDY DESIGN AND METHODS: Dual-needle apheresis procedures (n = 621) were p erformed in three centers, using either fixed interface positioning (FIP) o r periodic alternating interface positioning (PAIP). The other separation p arameters (e.g., anticoagulant: whole-blood ratio, and blood flow) were set individually. All platelet concentrates were evaluated for platelet yields and contaminating WBCs. RESULTS: The introduction of the PAIP resulted in a significant (p < 0.001) reduction in contaminating WBCs (median, 30,000) from the numbers seen wit h FIP (median, 2,300,000) while maintaining the separation efficacy (47%) a nd separation time. Ninety-eight percent of all concentrates contained less than 5 x 10(6) WBCs per concentrate and 92 percent contained less than 1 x 10(6). CONCLUSION: Plateletpheresis using the AS TEC 204 cell separator with PAIP is a valid alternative to WBC reduction by filtration. It may provide WBC-r educed platelet concentrates without the additional cost of filters. Howeve r, the reliability of the WBC reduction is not yet advanced enough that PAI P can be employed without any monitoring of the end product.