Comparison of Flow Cytometric Methods for the Enumeration of Residual Leucocytes in Leucoreduced Blood Products: A Multicenter Study.

The BD FACSVia™ System features novel designs in hardware, software, and instrument QC. We compared the performance of the BD FACSVia System using the BD Leucocount™ kit with the BD FACSCalibur™ flow cytometer. Leucoreduced platelet (PLT, n = 252) and red blood cell (RBC, n = 278) specimens were enrolled at four sites. Each specimen was stained in four tubes using the BD Leucocount kit reagents and acquired on the two systems. BD Leucocount Control cells (high and low) were used to evaluate the inter-site reproducibility on the BD FACSVia System at three sites over 20 days. Deming regression and Bland-Altman analysis were performed to determine the WBC absolute counts on the BD FACSVia System vs. the BD FACSCalibur system. Assay accuracy for the range of 0-350 WBCs/µl was adequate. For samples with <25 WBCs/µl, the bias with 95% limits of agreement was 0.136 (-1.897 to 2.169) WBC/µl for PLTs (n = 184) and 0.170 (-2.025 to 2.365) WBC/µl for RBCs (n = 193). For inter-site reproducibility, the CV% was 6.46% (upper 95% CI 7.16%) for the PLT high control and 9.49% (10.52%) for the PLT low control. The CV% was 7.51% (8.32%) for the RBC high control and 10.76% (11.92%) for the RBC low control. The BD FACSVia System reported equivalent results of WBC absolute counts for leucoreduced PLT and RBC samples compared to the BD FACSCalibur system. The inter-laboratory reproducibility of the BD FACSVia System met study specifications. © 2018 The Authors. Cytometry Part A Published by Wiley Periodicals, Inc. on behalf of ISAC.

The influence of conditions utilized to hold apheresis and whole blood-derived platelet samples before platelet enumeration with three hematology analyzers.

BACKGROUND: The Advia 120 (Siemens Diagnostics) hematology analyzer is different from other hematology analyzers in that it requires platelets (PLTs) to be "effectively spherical" to be counted. Our study evaluated how PLT counts with this hematology analyzer and two other models were influenced by the holding of PLT product samples. STUDY DESIGN AND METHODS: Samples were prepared from apheresis PLT products (APs) collected in ACD-A and from whole blood-derived PLT concentrates (PCs) in CP2D or ACD-A. Samples were stored in K(2) and K(3) ethylenediaminetetraacetate (EDTA) tubes at room temperature (RT) and in the cold. PLT counts were determined immediately, after 1 and 4 hours, and after an overnight hold, using Advia 120, XE-2100D, and Cell-Dyn 3700 hematology analyzers. RESULTS: A time-dependent increase in PLT counts was observed with AP samples held at RT using the Advia 120, but not with the other two hematology analyzers. AP samples held in the cold did not show a substantial time-dependent increase with any of the hematology analyzers. With the Advia 120, the PLT counts in the immediate samples were approximately 14% lower compared to those in cold or overnight-held RT samples. PC samples with all holding conditions and hematology analyzers did not show any substantial time-dependent increase in counts. CONCLUSIONS: With the Advia 120 hematology analyzer, the time-dependent increase in PLT counts with RT-held samples may be related to the need to have effectively sphered PLTs unlike that with the other two hematology analyzers. The absence of a holding effect with PC samples may indicate that only AP samples have population(s) that are slow to convert to spherical PLTs.

Reevaluation of the resting time period when preparing whole blood-derived platelet concentrates with the platelet-rich plasma method.

BACKGROUND: The resting of platelet (PLT) pellets during the preparation of whole blood-derived PLT concentrates (PCs) is considered an essential step. A reevaluation of the rest period was conducted because preparation and storage conditions have been modified during the past 20 years. STUDY DESIGN AND METHODS: A two-site in vitro study (Study 1) was conducted with rest times of 0 to 5 minutes, 1 hour, and 4 hours (n = 31-33 per rest period). Leukoreduced PCs were stored for 5 days. A second study (Study 2) measuring in vivo viability was conducted at a third site (14 paired studies). PCs were prepared from 2 units of whole blood on the same day to simultaneously compare viability following storage and radioisotopic labeling. RESULTS: In Study 1, comparable in vitro parameters and swirling were observed with the three rest periods. The mean (+/-1 SD) values after storage for the extent of shape change and hypotonic stress parameters were 0 to 5 minutes, 16.7 +/- 7.2 and 66.0 +/- 15.7%; 1 hour, 19.1 +/- 6.9 and 69.3 +/- 17.9%; and 4 hours, 17.6 +/- 5.5 and 64.1 +/- 11.3%. In Study 2, the in vivo recovery was 49.9 +/- 15.3 and 50.9 +/- 20.2% with 0- to 5-minute and 1-hour rest periods, respectively. The corresponding survival time was 111.2 +/- 50.7 and 114.9 +/- 43.8 hours. CONCLUSION: These studies indicate comparable in vitro and in vivo viability properties with 0- to 5-minute and 1-hour rest periods and at 4 hours (in vitro only).