(P-BC-36) Evaluation of Interim Platelet Units from an Automated Whole Blood Processing System

Background/Case Studies: With the first US Food and Drug Administration approval of an automated whole blood processing system that separates whole blood into red cells, plasma, and platelets in a single run, US based blood centers are evaluating efficiencies and benefits of implementing this new technology. Upon completion of the run, the device provides product data including plasma volume and a platelet yield index (PYI), which is intended to correlate to the platelet yield of the product. Since the PYI value can be utilized to guide further manufacturing/pooling, this value was evaluated versus the actual platelet yield of the interim platelet units (IPUs) to determine its potential use.

Study

Design/Methods: Forty-one whole blood collections were processed on the automated whole blood processing system utilizing the 3 component program which creates a red cell, plasma, IPU, and residual leukocyte. A sample from the IPU was obtained and tested on a hematology analyzer to obtain the platelet concentration. The PYI is calculated by the device utilizing an algorithm and information from the line sensor that monitors the platelet layer during the expression phase of the platelet product. Utilizing the platelet concentration and volume of the product, the platelet yield was calculated and compared to the instrument generated PYI using a Pearson R value and an R-squared value.

Results/Findings: When comparing the platelet yields to the PYI value, the Pearson R value was determined to be 0.90 and the R-squared value was determined to be 0.81 indicating a strong correlation between the PYI and the actual yield of the IPU (Figure 1). Upon further evaluation of the data, nine of the IPUs fell below the required 5.5 x 10¹⁰ platelets/unit as cited in AABB Blood Banks and Transfusion Services, standard 5.7.4.20. All nine of these platelets had a PYI of less than 50, with 7 of the 9 having a PYI less than 40. No platelets with a PYI less than 40 had a yield greater than 5.5 x 10¹⁰ platelets/unit. With guidance from the manufacturer, it was decided to discard interim platelet products with a PYI of less than 35. In utilizing this criteria, 92.7% of the IPUs meet the 5.5 x 10¹⁰ platelets/unit criteria.

Conclusions: The platelet yield index generated by the automated whole blood processing system provides an accurate estimate of actual platelet yield that can be used to guide pooling practices for optimization of final platelet yields.