[Analysis of the quality of hemoderivatives obtained using a buffy-coat extraction system with a top-and-bottom technique (Optipress II)].

Purpose: The aim of the present study is to know the results of the quality analysis of blood components processed with a Top & Bottom system (Optipress II) as a routine method in our blood bank, and compare it with the CE recommendations for quality of blood components.

Material and methods: Blood was collected in triple CPD-SAGM bags (Optipac, Baxter) and whole blood (WB) were centrifuged at 4,158 g, 14 min. Blood separation was performed by an automated Top & Bottom system (Optipress II), in which parameters were individually configured in preliminary trials. The buffy-coat (BC) layer was maintained within the configured levels during the separation process and remained into the original bag, whereas red cells (RBC) were collected into the bottom satellite bag (with 100 mL of SAGM) and fresh plasma (FP) was sent to the top satellite bag. Platelet concentrate (PC) was prepared by two different ways: 4 isogroup buffy-coats units were pooled by means of a sterile connector device (TSCD-201, Terumo) before a low centrifugation (1,040 g, 9 min) and the supernatant (4BC-PC) was transferred into a PL732 bag (Fenwal, Baxter); the other PC was prepared from one unit of BC by additioning approximately 70 mL of FP before centrifugation (321 g, 6 min) and following transference of the platelet concentrate (1BC-CP) into a 300 mL (Teruflex, Terumo) transfer bag. Both, 4BC-PC and 1BC-PC, were stored in a flat agitator at 22 degrees C to up five days after collection. We determined cell counts, haemoglobin, and hematocrit in a Sysmex K-800 cell counter in WB and blood components. Nageotte chamber was used when low white blood cells (WBC) counts were obtained. We also determined pH values on day five at 22 degrees C in a Crison 2000. Weights were measured and volumes were calculated using specificity gravity. Statistical analysis were carried out by Kolmogorov-Smirnov test as a normality distribution test, t-test for parametrical values and Wilcoxon-test as a no parametrical test (p < 0.05 was considered as Wilcoxon a significant value between different samples).

Results: The best parameters to configure the system were: strength: 25; BC volume: 33-35; level of BC: 5.5. RBCs (n: 1434) volume was 279 +/- 20 mL with 54.92 +/- 7.16 g of haemoglobin. More than 96% units had less than 1.2 x 10(9) WBC. FP volume (n: 803) averaged 279 +/- 19 mL with a WBC contamination less than 0.1 x 10(9)/L in all examined samples (n: 23). Platelet recovery in BC 92 +/- 9 percent of platelets present in WB, the percentage of removed leukocytes was 74 +/- 10 and between 13 and 15% of RBCs were lost in the BC (CI 95%). The BC volume (n: 1037) fitted the target volume of 60 mL (59-61 mL, CI 95%) except in some devices, where Optipress II lost the configuration for this parameter. 4BC-CPs (n: 325) showed a platelet yield per unit greater than 1BC-CPs (226). In addition, 80.3% of 4BC-CPs yielded more than 0.6 x 10(11) platelets per unit, whereas this criteria was only met in 59.7% of 1BC-CPs (p < 0.001). The ratio volume oper 10(9) platelets in 1 BC-CPs was significantly higher (1.57 mL) than 4BC-CPs (1.31 mL), and a greater level of 1BC-CPs (58.8%) showed pH values within 6.5-7.4 after 5 days of storage in comparison with 4BC-CPs (44.25%) (p < 0.001).

Conclusions: Optipress II provides standardized and poor leukocytes blood components. CE requirements were met in a great percentage of red-cell concentrates with less than 92 and 74 percent of original platelets and leukocytes, respectively and a low loss of haemoglobin per unit. Plasma volume obtained with this system represents an optimal yield. Top and Bottom technique allowed us to reduce the number of blood units per platelet concentrate, from six to four units with similar platelet yield compared to traditional procedures. Nevertheless, we must improve the storage conditions, in orter to satisfy all the CE requirements for platelet concentrates.