Residual cell content in plasma produced by three centrifugal apheresis procedures

BACKGROUND: Understanding the impact of collection procedures on the residual amount of blood cells in plasma for transfusion and for fractionation is of current interest. This prospective work evaluated plasma donations collected on an apheresis machine (PCS 2, Haemonetics) with three different automatic centrifugal apheresis procedures, currently largely used in the US (Revision G) and in Europe (Revision F), and included a new procedure that uses a high-separation core (HSC) that is designed with a second separation chamber to further separate cells from plasma. STUDY DESIGN AND METHODS: A total of 90 collection procedures have been performed from a population of 37 donors, under comprehensively standardized conditions. There were 30 well-matched donors in each group. Plasma aliquots were taken from the plasma units within 30 minutes of the end of the collection procedures and immediately assessed for WBCs, RBCs, PLTs, and supernatant Hb. RESULTS: In Revision F and Revision G plasma donations, the mean numbers of WBCs were 83.1 × 10⁴ and 311 × 10⁴ per L; PLTs, 5.01 × 10⁹ and 20 × 10⁹ per L; and RBCs, 58 × 10⁹ and 43 × 10 ⁹ per L, respectively. Significantly lower values were found with the HSC procedure (mean WBC, RBC, and PLT counts, 3.01 × 10⁴/L [p <0.05], 9 × 10⁶/L [p <0.001], and 3.5 × 10⁹/L [p <0.001], respectively). The amount of free Hb was similar in all three procedures. CONCLUSION: Significant differences in numbers of cells in plasma were found depending on the centrifugal procedures used and the design of the separation bowl. The lowest level of cell contamination was found with the new HSC bowl, which without a filtration step, yielded plasma that met the standard for WBC-reduced plasma. Plasma collectors can select the most appropriate method of plasma collection based on donor criteria, use of plasma (transfusion, viral inactivation, or fractionation), and local or international regulations, when in place.