Quality assessment and transfusion efficacy of buffy coat-derived platelet concentrates washed with platelet additive solution.

BACKGROUND: Transfusion of washed platelet concentrates (W-PC) is recommended for some patients, such as those who have had previous severe allergic transfusion reactions. However, we still lack a standardised method for preparing these products. Here, we assessed the effect of a manual washing procedure on in vitro platelet quality and on the transfusion efficacy of W-PCs. MATERIALS AND METHODS: Buffy coat-derived W-PC in Composol solution were prepared by one-step centrifugation. Platelet activation and function were evaluated before and after washing by means of: (i) CD62 expression by flow cytometry; (ii) platelet aggregation (LTA); and (iii) the VerifyNow® P2Y12 test. A pilot prospective transfusion study was carried out in 11 onco-hematology patients receiving, in a short time, two consecutive transfusions: one with standard PC (S-PC) and one with W-PC. The post-transfusion platelet increment, the 1 h and 24 h corrected count increment (CCI) and occurrence of bleeding events were used as indices of transfusion efficacy. RESULTS: Platelet recovery in W-PC was 84.8±5.4%. Washing slightly increased platelet activation in W-PC vs pre-washed samples (% CD62+ platelets 23.6±7 vs 14.8±1; p=0.03). As compared to prewash samples, platelet reactivity of W-PC as measured by VerifyNow® P2Y12 was significantly lower with ADP (PRU 32.2±37.7 vs 4.2±2.4, p=0.027), but similar using TRAP. Platelet aggregation responses to TRAP, collagen, ristocetin and arachidonic acid were maintained in W-PC. The pilot transfusion trial showed similar 1 h (13.5±5.6 vs 11.5±7.3, p=0.49) and 24 h (11±7.2 vs 9±6.5, p=0.48) CCI for S-PC and W-PC. Transfusion of W-PC was not associated with an increased number of bleeding events. DISCUSSION: We have set up a simple method to obtain buffy-coat-derived W-PC, which has minor effects on in vitro platelet quality and transfusion effectiveness. This procedure can be easily implemented in transfusion centres for on-demand preparation of washed platelets.

Evaluation of four rapid methods for hemoglobin screening of whole blood donors in mobile collection settings.

INTRODUCTION: Predonation hemoglobin measurement is a problematic requirement in mobile donation settings, where accurate determination of venous hemoglobin by hematology analyzers is not available. OBJECTIVE: We have evaluated hemoglobin screening in prospective donors by the semiquantitative copper sulphate test and by capillary blood samples analyzed by three portable photometers, HemoCue, STAT-Site MHgb, and the CompoLab HB system. METHODS: Capillary blood samples were obtained from 380 donors and tested by the copper sulphate test and by at least one of the named portable photometers. Predonation venous hemoglobin was also determined in all donors using a Coulter Max-M analyzer. RESULTS: The three photometers provided acceptable reproducibility (CV below 5%), and displayed a significant correlation between the capillary blood samples and the venous hemoglobin (R2 0.5-0.8). HemoCue showed the best agreement with venous hemoglobin determination, followed by STAT-Site MHgb, and the CompoLab HB system. The copper sulphate test provided the highest rate of donors acceptance (83%) despite unacceptable hemoglobin levels, and the lowest rate for donor deferral (1%) despite acceptable hemoglobin levels. The percentage of donors correctly categorized for blood donation by the portable hemoglobinometers was 85%, 82%, and 76% for CompoLab HB system, HemoCue and STAT-Site, respectively. CONCLUSION: Our data suggest that hemoglobin determination remains a conflictive issue in donor selection in the mobile setting. Without appropriate performance control, capillary hemoglobin screening by either the copper sulphate method or by the novel portable hemoglobinometers could be inaccurate, thus potentially affecting both donor safety and the blood supply.

Detection of free hepatitis C virus core antigen by enzyme-linked immunosorbent assay is not suitable for screening of granulocyte colony-stimulating factor-mobilized hematopoietic progenitor donors.

BACKGROUND: Recent studies have shown that hepatitis C virus (HCV) can be detected in peripheral blood mononuclear cells of patients who are negative for the presence of anti-HCV and serum HCV RNA. The aim of the study was to evaluate the prevalence of HCV viremia in granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood progenitor cell (PBPC) donors by the use of a free HCV core antigen enzyme-linked immunosorbent assay (ELISA). STUDY DESIGN AND METHODS: A total of 28 samples from consecutive PBPC donors that were mobilized with G-CSF, and 13 samples from patients presenting with leukocytosis of greater than 20 x 10(9) per L from other causes, were tested by a free HCV core antigen ELISA. Positive samples were confirmed by use of neutralization assays. The specificity of the assay was studied in 48,911 healthy blood donors negative for the presence of anti-HCV. RESULTS: The free HCV core antigen assay showed a 46.4 percent positivity in PBPC donors mobilized with G-CSF and 61.5 percent in patients exhibiting leukocytosis in the absence of G-CSF treatment. All the samples were found to be false-positive samples, and those related with growth factor treatment did not react when G-CSF was discontinued. Overall specificity by the test in freshly collected blood donor specimens was 99.62 percent. CONCLUSION: Data indicate that the free HCV core antigen ELISA is not a valid test in diagnosing HCV infection in G-CSF-treated PBPC donors. Moreover, false-positive results of this test on blood donors might be indicative of elevated white blood cell numbers. The low specificity of this assay in the PBPC mobilization setting suggests that molecular assays should be the test of choice in the screening of G-CSF-treated donors.

Evaluation of a new whole-blood filter that allows preparation of platelet concentrates by platelet-rich plasma methods.

BACKGROUND: A novel WBC-reduction in-line whole-blood (WB) filter that does not retain platelets was evaluated to assess the filtration performance and, after processing WB by the platelet-rich plasma (PRP) method, to analyze the storage quality of filtered platelet concentrate (PC) units. STUDY DESIGN AND METHODS: To analyze the filter retention, blood was collected from random donors into quadruple blood packs with an integral in-line filter (Imuflex WB-SP, Terumo; n = 25) or in standard triple bag systems (n = 30). To assess the in vitro storage characteristics of platelets, 26 WB units were pooled in pairs and redistributed into 13 units that underwent WBC reduction and 13 units that were not WBC reduced. In all cases, WB was separated into RBCs, PCs, and plasma by the PRP method and platelet function was compared. RESULTS: The filtration procedure led to RBC and PC WBC-reduced products that met the AABB and European requirements. The average filtration time was 30 minutes, the filter retained about 45 mL of WB, and there was no further loss of RBCs during the fractionation procedure. In vitro PC storage characteristics of the filtered units were similar to those of the nonfiltered units. CONCLUSION: A 4- and 3-log WBC reduction was observed in RBC and PC units that were produced by the PRP method, with a mean residual WBC content of 0.24 +/- 0.38 x 106 and 0.02 +/- 0.03 x 106 per unit, respectively. The procedure, performed under relatively simple logistics, results in good-quality, standard components that may reduce costs and ease the process of WBC reduction in transfusion services.