Vox Sanguinis最新文献

Background and objectives: To test the performance of a new droplet digital polymerase chain reaction (ddPCR) non-invasive foetal blood group and platelet antigen genotyping assay in the setting of a Dutch reference laboratory for foetal blood group and platelet antigen genotyping. Our population comprised 229 consecutive alloimmunized pregnant women who presented between April 2022 and March 2023 with 250 requests for non-invasive foetal RHD, RHE, RHc, RHC, K1, HPA-1a or HPA-5b blood group and platelet antigen genotyping.

Materials and methods: Samples were genotyped for blood group and platelet antigen alleles along with methylated RASSF1a (mRASSF1a) and sex-determining region of Y (SRY) and DYS14 as positive foetal controls. Negative blood group and platelet antigen results were issued only when foetal controls were positive; otherwise, such samples were classified as inconclusive.

Results: The assay achieved a success rate of 98.4% (246 of 250) because one case was lost to follow-up, one case was solved with quantitative polymerase chain reaction (qPCR) and one case precluded foetal typing due to RHD variant mothers. Only 10 cases needed a second sample and one case a third for a valid final result. We identified 116 maternal-foetal blood group and platelet antigen incompatibilities.

Conclusion: Clinical non-invasive foetal blood group and platelet antigen typing of alloimmunized pregnant women via ddPCR is successful and represents an improvement over qPCR because of the addition of a foetal control and because ddPCR circumvents potential interference from maternal cell-free DNA (cfDNA) background for foetal HPA-1 and K1.

Background and objectives: Canadian Blood Services defers donors during and for 4 months after oral pre-exposure or post-exposure prophylaxis (PrEP/PEP) for human immunodeficiency virus (HIV) because of concerns about altered viral kinetics. We assessed the impact of the switch from a time-based deferral for men who have sex with men (MSM) to sexual risk behaviour criteria on PrEP/PEP deferrals.

Materials and methods: Data on PrEP/PEP deferral codes were extracted from our National Epidemiology Database for the 22 months before (Period 1) and after (Period 2) the criteria change.

Results: PEP deferrals remained stable (2.3 vs. 1.7 per 100,000 donations in Periods 1 and 2, p = 0.2892), about 45% and 33%, respectively, of these donors who reported a recent needle stick injury. PrEP deferrals increased from 5.9 to 12.4 per 100,000 (p = 0.0001); approximately 30% of donors in both periods had other HIV risk factor deferrals. Donors deferred for PrEP use alone were more likely to be male, first-time users and younger than other donors.

Conclusion: The switch to sexual risk behaviour led to a small increase in deferrals for PrEP. We may not be measuring the full impact of deferral criteria because potential donors may self-defer and PrEP use is increasing.

The social market economies of the Western world considered the provision of plasma derivatives produced from publicly owned blood services as a legitimate state commitment and, until the last decades of the 20th century, many of the relevant jurisdictions maintained state-supported fractionation plants to convert publicly collected plasma into products for the public health system. This situation started to change in the 1990s, because of several converging factors, and currently, publicly owned/subsidized, not-for-profit fractionation activity has shrunk to a handful of players. However, the collection of plasma from publicly owned blood services has continued and recent developments have increased the interest of state authorities globally to increase the volume of plasma collected to increase the level of strategic independence in the supply of crucial plasma-derived medicines from commercial market pressures, particularly the global for-profit fractionation sector with its dominance of source plasma from paid donors in the United States. This paper reviews the development of the plasma industry and the evolution of the pressures on the supply of plasma, which has led to a situation of scarcity of key plasma-derived medicinal products (PDMPs).

Background and objectives: In the setting of trauma and suspected critical bleeding, indications to commence blood transfusions remain unclear, with high rates of potentially avoidable transfusions. Prehospital blood lactate measurements could help predict the need for blood transfusions. The aim of this study was to compare measurements detected by a point-of-care (POC) lactate device with laboratory measured lactate levels.

Materials and methods: This was a cross-sectional study conducted in the emergency department. Eligible patients were those with suspected major trauma and critical bleeding. Venous or arterial blood samples were collected. POC measurements of lactate levels were conducted using a StatStrip Xpress® lactate meter and compared with laboratory values.

Results: Among 70 patients, the mean difference between the POC and laboratory lactate results was -0.19 mmol/L, with limits of agreement at -1.9 and 1.5. Most measurements (n = 66; 94.3%) were within the limits of agreement. A POC lactate level of >3.3 mmol/L had >90% specificity for transfusion, whereas a level <1.4 mmol/L had 90% sensitivity to rule out a transfusion.

Conclusion: The level of agreement of POC lactate with the laboratory lactate was high. Research on clinical decision rules for pre-hospital transfusion that incorporate POC lactate measures is therefore feasible.

Background and objectives: In the setting of tissue hypoxia, S-nitrosylated haemoglobin (SNO-Hb) plays crucial roles in the control of blood flow. This is associated with decreased oxygen affinity to haemoglobin and increase in tissue oxygenation. Red blood cell (RBC) transfusion is primarily performed to improve tissue oxygenation in anaemic patients. RBCs after storage undergo a variety of biochemical and functional alterations, including deficiency of nitric oxide (NO) bioactivity. However, how donor characteristics affect NO levels during RBC storage is unclear. We sought to investigate the association of blood donor age, gender and storage duration with NO and SNO-Hb levels in blood units.

Materials and methods: Blood samples from 42 healthy younger (≤30 years) and older (≥45 years) donors were collected and stored for up to 42 days. Total NO kits were used to detect total nitrite and nitrate levels in blood storage solution. SNO-Hb levels in RBCs were detected and analysed by quantitative mass spectrometry.

Results: Total NO levels in the blood storage solution significantly increased with donor age and storage duration. Proteomic analysis revealed that RBCs from older donors, particularly older females, significantly lost SNO-Hb during storage. Our findings indicate that RBCs from older donors are associated with reduced SNO-Hb levels and increased NO metabolites in storage solution after ≥35 days storage.

Conclusion: The findings suggest stored RBCs from older donors may have reduced capacity to deliver oxygen to tissues under hypoxia. A shorter shelf life may be required for storing RBCs from older donors, particularly older females.

Background and objectives: Malaria risk deferral policies are important for mitigating the risk of transfusion-transmitted malaria and apply to all transfusable components, including plasma. While donors of plasma components are deferred for malaria risk in the United States, the viability of intraerythrocytic Plasmodium falciparum parasites present in human plasma components stored under different temperatures and durations has not been previously reported.

Materials and methods: We spiked human plasma with a low level of ring-stage P. falciparum-infected red blood cells and then determined their viability in cultures after storage at room temperature (22°C), refrigeration (4°C) and frozen conditions at -20 and -80°C.

Results: P. falciparum parasites spiked in human plasma remained viable after storage at 22°C for a maximum of 7 days. When stored at 4°C, parasites were viable after 1 and 3 days of storage and only for 1 day after storage at -20°C. Storage at -80°C had a cryopreserving effect and parasites remained viable for up to 176 days, the longest period tested.

Conclusion: P. falciparum parasites can survive for short durations in human plasma when stored at room temperature, or in refrigerated or frozen conditions at -20°C. However, when stored at -80°C, viable parasites were detected for up to 176 days, the maximum duration for which viability was assessed. In summary, Plasmodium parasites can survive in human plasma under different storage conditions and pose a risk of transfusion-transmitted infection.

Background and objectives: Pressures on the supply of plasma-derived medicinal products (PDMPs) have led to the efforts to increase the level of plasma collected by public health authorities.

Materials and methods: Public blood collectors were assessed regarding their routes towards domestically sourced plasma and PDMPs.

Results: The collectors' operations were specified and analysed. Models were classified according to the type of plasma collection system and contract fractionation arrangements.

Conclusion: Commitment and control to a public plasma collection system are the key features that need to underpin plasma collection.

Background and objectives: Anaemia is a treatable common condition with various aetiologies and is prevalent in hospitalized patients. However, anaemia is inconsistently worked up and treated in the inpatient setting, in part because there is no standardized inpatient diagnostic and treatment approach to anaemia. Therefore, the objective of this study was to examine the diagnostic approach and prevalence of common aetiologies of anaemia in hospitalized patients and test for an association between aetiologies of anaemia and patient characteristics.

Materials and methods: This study is a prospective observational study of hospitalized adult patients with anaemia. Patient laboratory data were used to assess the frequency of anaemia diagnostic workup and common aetiologies of anaemia.

Results: In a sample of 945 patients (mean age 58 years, 57% female and 72% Black), 30% patients had chronic anaemia, 11% had multifactorial anaemia, 5% had iron deficiency and 37% had insufficient laboratory data to determine their anaemia aetiology (unidentified aetiology). Patients with an unidentified aetiology received fewer transfusions and were more likely to be White, have longer hospital stays and have higher nadir haemoglobin levels.

Conclusion: A significant portion of hospitalized patients with anaemia did not have an identified aetiology. A standardized diagnostic algorithm could decrease this number and help patients receive appropriate treatment.

Background and objectives: Serum immunoglobulin G (IgG) and total protein are used to monitor plasmapheresis donor safety. However, there is a lack of information from large donor cohorts to determine the best use of these measurements.

Materials and methods: We identified 230,144 plasmapheresis donors making their first donation between 1 July 2020 and 31 March 2024. IgG and total protein were measured prior to the first donation and then annually, following our donor safety monitoring protocol. We considered individuals who had not donated for 12 months to estimate intra-individual biological variability of IgG. We compared four models to predict which donors would develop IgG < 6 g/L.

Results: The IgG reference interval for the cohort was 7.67-15.6 g/L. IgG declines 5%-11% after the age of 45 years. The intra-individual biological variability of IgG (5.2%) is small, indicating that there is homeostatic set point for individual IgG. IgG is reduced by plasmapheresis but recovers to recruitment level after 12 weeks. When plasma is donated every 2-3 weeks, mean IgG plateaus 1 g/L below recruitment concentration. IgG at recruitment is the best predictor of which donors will have IgG < 6 g/L after a year of donations. Total protein is a low-value test in this context.

Conclusion: Plasmapheresis is safe and sustainable for almost every donor, at the 2-weekly frequency allowed in Australia. The donors most likely to experience unacceptably low IgG are those with very low recruitment IgG levels. These donors could be recommended 12-week intervals between donations or other donation types.

Background and objectives: Access to blood components in pre-hospital bleeding resuscitation is challenging. Dried plasma is a logistically superior alternative, and new products are emerging. Therefore, we aimed to evaluate laboratory and practical differences in three differently produced dried plasma products.

Materials and methods: Single-donor lyophilized LyoPlas®, pooled-donor, lyophilized and pathogen-reduced OctaplasLG Powder®, and single-donor sprayed-dried FrontlineODP™ along with fresh plasma (in-house, pre-FrontlineODP and OctaplasLG) as controls were analysed (n = 8). Laboratory tests included measurements of various coagulation factors and thromboelastography. The practical evaluation of the dried plasma products included preparation time, time to dissolve the dried plasma and total time, together with subjective opinions from eight clinical users.

Results: The coagulation factor content was within human reference ranges for all dried plasma, with approximately 10%-20% loss compared with fresh plasma. More variations were observed in the single-donor products compared with the pooled products. Clot formation analysed by thromboelastography showed normal graphs. Reconstitution time was similar, ranging from on average 7-9 min. In the user evaluation, the reconstitution time and the possibility of using a plastic bag for the transfusion were emphasized as important, the latter fulfilled by two of the products.

Conclusion: The study supports that dried plasma may be produced with lyophilization or spray-drying technique, as well as with the addition of pathogen reduction, with preserved coagulation capability. The products were reconstituted in acceptable time and deemed feasible for pre-hospital use by eighth test users.