Application of the ADVIA cerebrospinal fluid assay to count residual red blood cells in blood components

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer

Background

Manufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two‐site appraisal of the system.

Study Design and Methods

Performance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration.

Results

Linearity studies up to 19 000 RBCs/μL demonstrated good correlation between expected and observed results (R² ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R² = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/μL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/μL) than those produced with the buffy coat method either manually (median, 681 RBCs/μL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/μL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/μL were also detected by the BB mode.

Conclusion

The BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Evaluation of urine dipsticks for quality control of residual erythrocytes and leukocytes in leukocyte-depleted donor plasma

Currently used methodologies for quality control of residual leukocytes and erythrocytes in leukocyte-depleted plasma are either expensive or time-consuming. It has been proposed that urine dipsticks could be used as a screening method for residual erythrocytes. The aim was, therefore, to evaluate if urine dipsticks could be used to detect residual erythrocytes and also residual leukocytes in leukocyte-depleted plasma. Dilution series ranging over the decision limits for residual erythrocytes and leukocytes were prepared. Positive, negative and overall agreements, as well as the precision and joint frequency distributions, were calculated for five dipstick analyzers and their corresponding dipsticks. Twenty-four consecutive leukocyte-depleted donor plasma samples were also tested. None of the dipstick analyzers had both a high positive and a high negative agreement. Accordingly, none of the analyzers were able to discriminate between cell concentrations close to the decision limits. The inconsistency count revealed differences in precision between the dipstick analyzers. In the 24 consecutive donor samples, no significant correlation between the dipstick analyzers and the reference methods were found. In conclusion, urine dipsticks are not suitable for quality control of residual leukocytes and erythrocytes in leukocyte-depleted donor plasma.

Evaluation of a routine hematology analyzer for quality control of leukoreduced plasma

BACKGROUND

Quality control of residual white blood cells (WBCs) and red blood cells (RBCs) in leukoreduced plasma is mandatory. Although technological advances have been made, analysis of quality controls using routine hematology analyzers has not generally been introduced. The aim of this study was to evaluate if the routine hematology analyzer Sysmex XN-10, (Sysmex Nordic ApS) could be used for quality control of residual WBCs and RBCs in leukoreduced plasma.

STUDY DESIGN AND METHODS

Linearity, accuracy, and precision were established for two Sysmex XN-10 analyzers using spiked donor plasma. ADAM rWBC (NanoEnTek) and manual counting in the Bürker chamber (NanoEnTek) were reference methods for WBCs and RBCs, respectively. Twenty-five consecutive leukoreduced donor plasma samples were also tested.

RESULTS

For WBCs, the linearity criteria were met for the ADAM rWBC, but not for the Sysmex XN-10 instruments. Precision on both Sysmex XN-10 instruments was accurate only at 6 cells/μL, and accuracy was consistently acceptable only at 5 to 6 cells/μL. The precision and accuracy of the ADAM rWBC were acceptable at 2 to 6 cells/μL. For RBCs, both Sysmex XN-10 instruments and manual counting in the Bürker chamber were linear and fulfilled the precision criteria. Accuracy was acceptable for both Sysmex instruments at 6 to 12 × 10⁹ WBCs/L but fluctuated within the study's measuring range for the Bürker chamber. No false-positive results were seen in the 25 consecutive donor plasma samples tested.

CONCLUSION

For quality control purposes of leukoreduced plasma, the Sysmex XN-10 analyzer is suitable for the enumeration of residual RBCs but not of residual WBCs.

Shifting ground and gaps in transfusion support of patients with hematological malignancies

The transfusion support of hematological malignancies considers 2 dimensions: the quantity of what we order (in terms of triggers, doses, targets, and intervals), and the special qualities thereof (with respect to depths of matching and appropriate product modifications). Meanwhile, transfusion-related enhancements in the quantity and quality of life may not be dose dependent but rather tempered by unintended patient harms and system strains from overexposure. Evidence and guidelines concur in endorsing clinically noninferior conservative red blood cell (RBC) transfusion care strategies (eg, triggering at hemoglobin <7-8 g/dL and in single-unit doses for stable, nonbleeding inpatients). However, the unique subpopulation of patients with hematological malignancies who are increasingly managed on an outpatient basis, and striving at least as much for quality of life as quantity of life, is left on the edges of these recommendations, with more questions than answers. If a sufficiently specific future wave of evidence can satisfy the concerns (and contest the assumptions) of the remaining proponents of liberalism, and if conservatism is broadly adopted, savings may be potentially immense. These savings can then be reinvested to address other gaps and inconsistencies in RBC transfusion care, such as the best achievable degrees of prophylactic antigen matching that can minimize alloimmunization-related service delays and reactions.

Routine Screening Method for Microparticles in Platelet Transfusions

Platelet inventory management based on screening microparticle content in platelet concentrates is a new quality improvement initiative for hospital blood banks. Cells fragment off microparticles (MP) when they are stressed. Blood and blood components may contain cellular fragments from a variety of cells, most notably from activated platelets. When performing their roles as innate immune cells and major players in coagulation and hemostasis, platelets change shape and generate microparticles. With dynamic light scattering (DLS)-based microparticle detection, it is possible to differentiate activated (high microparticle) from non-activated (low microparticle) platelets in transfusions, and optimize the use of this scarce blood product. Previous research suggests that providing non-activated platelets for prophylactic use in hematology-oncology patients could reduce their risk of becoming refractory and improve patient care. The goal of this screening method is to routinely differentiate activated from non-activated platelets. The method described here outlines the steps to be performed for routine platelet inventory management in a hospital blood bank: obtaining a sample from a platelet transfusion, loading the sample into the capillary for DLS measurement, performing the DLS test to identify microparticles, and using the reported microparticle content to identify activated platelets.

Low frequency of anti-D alloimmunization following D+ platelet transfusion: the Anti-D Alloimmunization after D-incompatible Platelet Transfusions (ADAPT) study

The reported frequency of D alloimmunization in D- recipients after transfusion of D+ platelets varies. This study was designed to determine the frequency of D alloimmunization, previously reported to be an average of 5 ± 2%. A primary anti-D immune response was defined as the detection of anti-D ≥ 28 d following the first D+ platelet transfusion. Data were collected on 485 D- recipients of D+ platelets in 11 centres between 2010 and 2012. Their median age was 60 (range 2-100) years. Diagnoses included: haematological (203/485, 42%), oncological (64/485, 13%) and other diseases (218/485, 45%). Only 7/485 (1·44%; 95% CI 0·58-2·97%) recipients had a primary anti-D response after a median serological follow-up of 77 d (range: 28-2111). There were no statistically significant differences between the primary anti-D formers and the other patients, in terms of gender, age, receipt of immunosuppressive therapy, proportion of patients with haematological/oncological diseases, transfusion of whole blood-derived or apheresis platelets or both, and total number of transfused platelet products. This is the largest study with the longest follow-up of D alloimmunization following D+ platelet transfusion. The low frequency of D alloimmunization should be considered when deciding whether to administer Rh Immune Globulin to D- males and D- females without childbearing potential after transfusion of D+ platelets.