Blood Sample Volume Research Articles

Efficacy and speed of effect after the first dose of aspirin in children with congenital heart disease.

Many paediatric studies report that patients must be established on aspirin therapy for a minimum of 5 days to achieve adequate response. This is not always practical especially in critical settings. Prospective identification of patients that are unresponsive to aspirin sooner could potentially prevent thrombotic events. The aim of this study was to investigate prospectively if the first dose of aspirin is effective in decreasing platelet aggregation, and thromboxane formation and if this can be measured after 2 hours in paediatric cardiology patients. A secondary aim was to identify a cut-off for a novel marker of aspirin responsiveness the maximum amplitude with arachidonic acid, which could potentially dramatically reduce the blood volume required. Third, we aimed to prospectively identify potentially non-responsive patients by spiking a sample of their blood ex vivo with aspirin. The majority (92.3%) of patients were responsive, when measured 2 hours post first dose of aspirin. Non-response or inadequate response (7.7%) can also be identified at 2 hours after taking the first dose of aspirin. Additionally, we have shown a novel way to reduce blood sample volume requirements by measurement of the maximum amplitude with arachidonic acid as a marker of response, particularly for monitoring. These findings of rapid efficacy in the majority of patients offer assurance in a sound, practical way to attending clinicians, patients, and families.

DNA Methylation signatures underpinning blood neutrophil to lymphocyte ratio during first week of human life

Understanding of newborn immune ontogeny in the first week of life will enable age-appropriate strategies for safeguarding vulnerable newborns against infectious diseases. Here we conducted an observational study exploring the immunological profile of infants longitudinally throughout their first week of life. Our Expanded Program on Immunization - Human Immunology Project Consortium (EPIC-HIPC) studies the epigenetic regulation of systemic immunity using small volumes of peripheral blood samples collected from West African neonates on days of life (DOL) 0, 1, 3, and 7. Genome-wide DNA methylation and single nucleotide polymorphism markers are examined alongside matched transcriptomic and flow cytometric data. Integrative analysis reveals that a core network of transcription factors mediates dynamic shifts in neutrophil-to-lymphocyte ratios (NLR), which are underpinned by cell-type specific methylation patterns in the two cell types. Genetic variants are associated with lower NLRs at birth, and healthy newborns with lower NLRs at birth are more likely to subsequently develop sepsis. These findings provide valuable insights into the early-life determinants of immune system development.

Surface protein analysis of breast cancer exosomes using visualized strategy on centrifugal disk chip

Breast cancer, the most common cancer among women worldwide, lacks specific tumor markers for accurate diagnosis. Recent advances have highlighted tumor-derived exosomes as a promising non-invasive biomarker for cancer detection. Continuous monitoring of surface protein markers on exosomes in the blood could offer valuable insights for breast cancer diagnosis. However, integrating the isolation and detection of exosomes from whole blood is bulky, time-consuming, and requires professional operations. To address this difficulty, we developed a method of integrated centrifugal disk chip (CD chip) exosome enrichment directly from whole blood followed by a colorimetric visualization strategy for multiplex analysis. The disc consists of multi-chambers and multi-microchannels with immediate smartphone-enabled processing of colorimetric results. The combination of CEA + CA125 + EGFR on-chip detection could significantly differentiate the different stages of cancer in tumor-bearing mice and successfully distinguish between breast cancer patients and healthy individuals. Crucially, small volumes (100 μL) of blood samples were adequate. In addition, the chip was simple and fast, with results within 10 min, which provides immediate exosomal information through consecutive blood sampling, which could potentially result in a more timely and well-informed clinical breast cancer diagnosis.

A Plasmonic Nanoledge Array Sensor for Selective Detection of Cardiovascular Disease Biomarkers in Human Whole Blood.

Optical sensors face challenges when detecting ultralow amounts of analytes in whole blood, including signal quenching due to optical absorption and false positives due to nonspecific binding. This study introduces gold nanoscale array features termed nanoledges (NLs), which interact with incident white light to produce a transmitted surface plasmon resonance (tSPR) signal. This extraordinary optical transmission (EOT) spectrum occurs in the near-infrared (NIR) region, thereby minimizing signal quenching caused by visible-light absorption from blood proteins and pigments. To develop a sensitive, selective, and label-free optical biosensor for detecting various levels of cardiac troponin I (cTnI) in very small volumes of whole blood samples, DNA aptamers are tethered to the NL surface, specifically binding to the cTnI biomarker. This biological binding activity alters the refractive index at the NL surface, causing a peak shift in the EOT spectrum and enabling quantification of cTnI levels. The NL array chip demonstrated high sensitivity for cTnI detection in buffer, human serum (HS), and human whole blood (HB), with detection limits of 0.079, 0.084, and 0.097 ng/mL, respectively. Control measurements using blank target mediums and those containing up to 125 ng/mL of other proteins, such as myoglobin, creatine kinase, and heparin, showed minimal interference and high specificity. The NL plasmonic array's performance in biosensing underscores its promise for clinical analysis and its potential development as a point-of-care platform for early cardiovascular disease (CVD) diagnostics.

Whole Blood Theophylline Measurements Using an Electrochemical DNA Aptamer-based Biosensor

Theophylline, a bronchodilator used in the treatment of respiratory diseases, displays a narrow therapeutic range requiring therapeutic drug monitoring to maximize its effectiveness and safety. Current measurements of theophylline concentrations are, however, achieved using chromatography or immunoassays, which, in spite of their high accuracy and sensitivity, rely on expensive laboratory-based instruments operated by trained personnel or provide only semi-quantitative results, respectively. In response, we developed an electrochemical DNA aptamer-based (E-AB) sensor for theophylline on screen-printed electrodes. Our sensors enable rapid (<30 s) and selective measurements against theophylline structural analogs in clinically relevant range (55–110 μM) in finger-pricked-sized volumes of undiluted blood samples (<100 μL). Given these attributes, we envision that our results contribute to the development of a low-cost and convenient sensing device for molecular monitoring at the point-of-care.

Determination of metformin from micro-liter plasma and blood glucose test strip using eco-friendly micro-extraction procedures for point-of-care diagnostics

Metformin is commonly used in the treatment of type 2 diabetes and polycystic ovary syndrome. Beyond these common applications, it also holds promise in treating chronic pain, and as an antiaging and anticancer agent. In addition, it has cardiovascular protective and neuroprotective effects. However, elevated concentrations of metformin in the plasma, such as in patients with renal impairment or with conditions that can disrupt lactate clearance, could cause metformin-associated lactic acidosis. Moreover, metformin can cause a deficiency of vitamin-B12 and folic acid and impact one-carbon metabolism negatively. This study employs micro-extraction procedures to extract metformin from the human plasma and blood glucose test strips followed by detection using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Under the optimized micro-extraction procedures and by using an eco-friendly base and solvent, the proposed method required only 10 µL of the human plasma and a small piece of the blood glucose test strip for metformin analysis. The method exhibits a linear range of 0.05–5 μg mL−1 with a coefficient of determination (r2) of 0.999 and a limit of detection of 0.01 μg mL−1. The relative standard deviation (RSD) and relative error (RE) were both below 6.7 %. The test strip is a disposable product; its reuse before disposal could increase its additional applicability. Furthermore, major blood proteins and their modifications could be identified using this tiny volume of blood by mass spectrometry after protein digestion. The proposed technique could be invaluable in point-of-care diagnostics, enabling rapid monitoring of metformin plasma concentration and major plasma proteins to help patients mitigate the risk of metformin-associated lactic acidosis. To reduce organic waste in clinical applications, micro-extraction is a simple and efficient protocol for sample preparation using minute volumes of blood samples.

Small-volume blood sample collection tubes in adult intensive care units: A rapid practice guideline.

This Intensive Care Medicine Rapid Practice Guideline (ICM-RPG) provides an evidence-based recommendation to address the question: in adult patients in intensive care units (ICUs), should we use small-volume or conventional blood collection tubes? We included 23 panelists in 8 countries and assessed and managed financial and intellectual conflicts of interest. Methodological support was provided by the Guidelines in Intensive Care, Development, and Evaluation (GUIDE) group. We conducted a systematic review, including evidence from observational and randomized studies. Using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, we evaluated the certainty of evidence and developed recommendations using the Evidence-to-Decision framework. We identified 8 studies (1 cluster and 2 patient-level randomized trials; 5 observational studies) comparing small-volume to conventional tubes. We had high certainty evidence that small-volume tubes reduce daily and cumulative blood sampling volume; and moderate certainty evidence that they reduce the risk of transfusion and mean number of red blood cell units transfused, but these estimates were limited by imprecision. We had high certainty that small-volume tubes have a similar rate of specimens with insufficient quantity. The panel considered that the desirable effects of small-volume tubes outweigh the undesirable effects, are less wasteful of resources, and are feasible, as demonstrated by successful implementation across multiple countries, although there are upfront implementation costs to validate small-volume tubes on laboratory instrumentation. This ICM-RPG panel made a strong recommendation for the use of small-volume sample collection tubes in adult ICUs based on overall moderate certainty evidence.

Analysis of arterial blood gas values when discarding different volumes of blood samples in an arterial heparin blood collector during thoracoscopic surgery

BackgroundArterial blood gas analysis (ABGA) plays a vital role in emergency and intensive care, which is affected by many factors, such as different instrumentation, temperature, and testing time. However, there are still no relevant reports on the difference in discarding different blood volumes on ABGA values.MethodsWe enrolled 54 patients who underwent thoracoscopic surgery and analysed differences in blood gas analysis results when different blood volumes were discarded from the front line of the arterial heparin blood collector. A paired t test was used to compare the results of the same patient with different volumes of blood discarded from the samples. The difference was corrected by Bonferroni correction.ResultsOur results demonstrated that the PaO2, PaCO2, and THbc were more stable in the 4th ml (PaO2 = 231.3600 ± 68.4878 mmHg, PaCO2 = 41.9232 ± 7.4490 mmHg) and 5th ml (PaO2 = 223.7600 ± 12.9895 mmHg, PaCO2 = 42.5679 ± 7.6410 mmHg) blood sample than in the 3rd ml (PaO2 = 234.1000 ± 99.7570 mmHg, PaCO2 = 40.6179 ± 7.2040 mmHg).ConclusionIt may be more appropriate to discard the first 3 ml of blood sample in the analysis of blood gas results without wasting blood samples.

Stable measurement of chemistry, immunochemistry, and hematology analytes in a heparin-based anticoagulant with iloprost additive: A promising candidate for the polyvalent blood collection tube.

A polyvalent blood collection tube could potentially reduce the number and volume of blood samples drawn from patients and reduce the risk of tube mix-ups in a point-of-care setting in the emergency department and the intensive care unit. Four different concentrations of our experimental heparin anticoagulant with iloprost additive (HEP-ILOP 50 nM, 150 nM, 1000 nM, and 10 μM, respectively) were tested for significant differences and bias performance specifications against EDTA for 29 hematology analytes, and the highest concentration (HEP-ILOP 10 μM) against lithium heparin for 14 chemistry and immunochemistry analytes. Samples were drawn from 79 consenting subjects from the Oncology Department (n = 38) and the Intensive and Intermediary Care Unit (n = 41). For hematology analytes, the HEP-ILOP formulation generally provided stable measurement within optimal requirements within 5 h after sampling (mean 104 ± 56 min), with very little difference between the four HEP-ILOP concentrations. Because of differences in platelet and red blood cell swelling between EDTA and HEP-ILOP, all size-dependent analytes required proportional factorization to produce similar results. Platelet count by impedance similarly required factorization, whereas the fluorescent method provided results identical with EDTA. Chemistry and immunochemistry analytes were within optimal requirements except for potassium, lactate dehydrogenase, and glucose, indicating a cytoprotective effect of iloprost reducing cell metabolism and rupture, thereby producing results closer to in vivo conditions. Our novel dry-sprayed anticoagulant formulation, HEP-ILOP, is a promising candidate for a polyvalent blood collection tube, enabling the analysis of hematology, chemistry, and immunochemistry analytes in the same tube.

Microfluidic Capture Device for Simple, Cell Surface Marker-Based Quantification of Senescent CD8+ T Cells

Among human CD8+ T cells, senescent cells are marked by the expression of CD57. The frequency of senescent CD57+CD8+ T cells is significantly correlated with aging and age-associated disorders, and it can be measured by multi-color flow cytometry. However, multi-color flow cytometry presents challenges in terms of accessibility and requires significant resource allocation. Therefore, developing a rapid and straightforward method for quantifying CD57+CD8+ T cells remains a key challenge. This study introduces a microfluidic device composed of a PDMS microfluidic channel with a pre-modified glass substrate for anti-CD8 antibody immobilization. This design allows blood samples to flow through, enabling the selective capture of CD8+ T cells while minimizing the required blood sample volume. This technology enables accurate and reliable quantification of CD57+ cells among captured CD8+ T cells through fluorescence image analysis. The ability of the device to easily quantify senescent CD57+CD8+ T cells is anticipated to contribute significantly to both immunological research and clinical applications.

Effect of Minimization of Early Blood Sampling Losses Among Extremely Premature Neonates: A Randomized Clinical Trial

To evaluate the effect of blood sampling stewardship on transfusion requirements among infants born extremely preterm. In this single-center, randomized controlled trial (RCT), infants born at <28weeks of gestation and birth weight of <1000g were randomized at 24hours of age to two different blood sampling approaches: restricted sampling (RS) vs conventional sampling (CS). The stewardship intervention in the RS group included targeted reduction in blood sampling volume and frequency and point of care testing methods in the first 6weeks after birth. Both groups received early recombinant erythropoietin from day three of age. Primary outcome was the rate of early red blood cell (RBC) transfusions in the first six postnatal weeks. A total of 102 infants (mean gestational age: 26weeks; birth weight: 756g) were enrolled. Fidelity to the sampling protocol was achieved in 95% of the infants. Sampling losses in the first 6weeks were significantly lower in the RS group (16.8ml/kg vs 23.6ml/kg, P<.001). The RS group had a significantly lower rate of early postnatal RBC transfusions (41% vs 73%, RR: 0.56 [0.39-0.81], P=.001). The hazard of needing a transfusion during neonatal intensive care unit (NICU) stay was reduced by 55% by RS. Mortality and neonatal morbidities were similar between the two groups. Minimization of blood sampling losses by approximately one-third in the first 6weeks after birth leads to substantial reduction in the early red blood cell transfusion rate in infants born extremely preterm and weighing <1000g at birth. http://www.ctri.nic.in (CTRI/2020/01/022 964).

Verification of a method using magnetic bead enrichment and nucleic acid extraction to improve the molecular detection of bacterial contamination in blood components.

Bacterial contamination of blood products poses a significant risk in transfusion medicine. Platelets are particularly vulnerable to bacterial growth because they must be stored at room temperature with constant agitation for >5 days. The limitations of bacterial detection using conventional methods, such as blood cultures and lateral flow assays, include the long detection times, low sensitivity, and the requirement for substantial volumes of blood components. To address these limitations, we assessed the performance of a bacterial enrichment technique using antibiotic-conjugated magnetic nanobeads (AcMNBs) and real-time PCR for the detection of bacterial contamination in plasma. AcMNBs successfully captured >80% of four bacterial strains, including Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Klebsiella pneumoniae, in both plasma and phosphate-buffered saline. After 24-h incubation with bacterial enrichment, S. aureus and B. cereus were each detected at 101 CFU/mL in all trials (5/5), E. coli at 101 CFU/mL in 1/5 trials, and K. pneumoniae at 10² CFU/mL in 4/5 trials. Additionally, without incubation, the improvement was also achieved in samples with bacterial enrichment, S. aureus at 10² CFU/mL and B. cereus at 101 CFU/mL in 1/5 trials each, E. coli at 10³ CFU/mL in 3/5 trials, and K. pneumoniae at 10¹ CFU/mL in 2/5 trials. Overall, the findings from this study strongly support the superiority of bacterial enrichment in detecting low-level bacterial contamination in plasma when employing AcMNBs and PCR.IMPORTANCEThe study presents a breakthrough approach to detect bacterial contamination in plasma, a critical concern in transfusion medicine. Traditional methods, such as blood cultures and lateral flow assays, are hampered by slow detection times, low sensitivity, and the need for large blood sample volumes. Our research introduces a novel technique using antibiotic-conjugated magnetic nanobeads combined with real-time PCR, enhancing the detection of bacteria in blood products, especially platelets. This method has shown exceptional efficiency in identifying even low levels of four different species of bacteria in plasma. The ability to detect bacterial contamination rapidly and accurately is vital for ensuring the safety of blood transfusions and can significantly reduce the risk of infections transmitted through blood products. This advancement is a pivotal step in improving patient outcomes and elevating the standards of care in transfusion medicine.

Quantitation of circulating short-chain fatty acids in small volume blood samples from animals and humans

BackgroundThe role of gut microbiota in human health has been intensively studied and more recently shifted from emphasis on composition towards function. Function is partly mediated through formed metabolites. Short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate as well as their branched analogues represent major products from gut fermentation of dietary fibre and proteins, respectively. Robust and high-throughput analysis of SCFAs in small volume blood samples have proven difficult. Major obstacles come from the ubiquitous presence of SCFAs that leads to contaminations and unstable analytical results because of the high volatility of these small molecules. Comprehensive and comparable data on the variation of SCFAs in blood samples from different blood matrices and mammal species including humans is lacking. Therefore, our aim was to develop and evaluate a stable and robust method for quantitation of 8 SCFAs and related fermentation products in small volume blood plasma samples and to investigate their variation in humans and different animal species. ResultsDerivatization was a successful approach for measurement of SCFAs in biological samples but quenching of the derivatization reaction was crucial to obtain long-term stability of the derivatized analytes. In total 9 compounds (including succinic acid) were separated in 5 min. The method was linear over the range 0.6–3200 nM formic (FA), acetic (AA), 0.3–1600 nM propionic (PA), and 0.16–800 nM for butyric (BA)-, isobutyric (IBA)-, valeric (VA)-, isovaleric (IVA)-, succinic (SA) and caproic acid (CA). The precision ranged ≤12 % within days and ≤28 % between days (except for CA and VA) in three different plasma quality control (QC) samples (29 batches analyzed over 3 months). The extraction recovery was on average 94 % for the different SCFAs. Typical interquartile range (IQR) concentrations (μM) of SCFAs in human plasma samples were 168 μM (FA), 64 μM (AA), 2.2 μM (PA), 0.54 μM (BA), 0.66 μM (IBA), 0.18 μM (VA), 0.40 μM (IVA), and 0.34 μM (CA). In total, 55 samples per batch/day were successfully analyzed and in total 5380 human plasma samples measured over a 3-year timespan. SignificanceThe developed UHPLC-MS based method was suitable for measuring SCFAs in small blood volume samples and enabled robust quantitative data.

Simultaneously measure the concentrations of busulfan and phenytoin in human plasma using an HPLC-MS/MS method: Application to the TDM for children underwent hematological stem cell transplantation

AbstractIn this work, a simple and rapid high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed and validated to carry out the simultaneous measurement of busulfan (BU) and phenytoin (PHT) in the plasma of children. In this method, plasma sample could be prepared by one-step protein precipitation using 1 mL of methanol/water (1:1, v/v). After centrifugation (14,500 rpm, 5 min, 4 °C), 10 μL of the supernatant was injected into a Hypersil Gold C18 column (150 × 2.1 mm, 5 μm, Thermo Fisher Scientific) for separation by gradient elution. Quantification was carried out using multiple reactions monitoring (MRM) under positive scan mode. In the method verification, the calibration curves of BU and PHT showed satisfactory linearity (r &gt; 0.99) at the concentration ranging from 0.02 to 20 μg mL−1. The accuracy and precision were tested at four concentration levels (including the LLOQ level) with the relative error (RE) ranging from −0.80% to 11.45% and coefficient of variation (CV) between 0.93% and 7.74%. There was no pronounced matrix effect to interfere with the quantitative analysis. Compared to determine BU and PHT using two individual methods, less pre-treatment process, labor and blood sample volume are required in this proposed method. Finally, this method was successfully applied to the therapeutic drug monitoring of BU and PHT for children underwent hematological stem cell transplantation.

B-043 Thermal Evaluation and Field Study of Labcorp TrueThermTMpackaging System for Protecting Sub-Milliliter Blood Samples

Abstract Background Many diagnostic assays require temperature-controlled sample storage and shipment to ensure accuracy. Here we present, the Labcorp TrueTherm, designed for thermal-controlled shipment of small volume blood samples. The reusable TrueTherm combines a stainless steel vacuum bottle with a custom internal cold pack and insulating stopper. Users refrigerate the cold pack to protect against warm or cold temperature excursions. The whole system is relatively compact, measuring about 10in (25cm) in length, 3 inches (8cm) in diameter, and 2.5 pounds (1kg) in weight. Methods In order to evaluate thermal performance, the TrueTherm system was exposed to both ISTA-7D summer and winter conditions and internal temperature was recorded for 96hrs. Subsequently, venous blood samples were collected from n = 40 subjects, and immediately aliquoted into BD SST (Serum separator) Microtainers®. For each subject, sub-samples were subjected to centrifugal separation (provided by the Labcorp TrueSpinTM battery-powered centrifuge), serum removal, and 24hr insulated shipping on ice packs compared to a variety of 72hr cross-country shipping conditions with and without centrifugal separation and with and without insulated packaging (including TrueTherm) during August 2022. Results TrueTherm maintained temperature between 2 and 20C for 72hrs under simulated summer and winter conditions. Under actual cross-country summer commercial shipping conditions, both centrifugal separation and thermal control via TrueTherm expanded the number of valid analytes compared to unprotected whole blood (see Table 1). Conclusion The results suggest that TrueTherm is an effective system for protecting small blood samples from thermal extremes during extended shipping. Portable thermal moderation was complimentary with portable centrifugal separation to maximize stability of common analytes.

Evaluation of a Compact, Portable Centrifuge for Separating Microvolume Blood Samples at the Point of Collection.

The increased demand for decentralized blood sample collection presents numerous operational challenges for diagnostics providers. Sample degradation including sample hemolysis due to time, temperature, and handling between collection and laboratory analysis leads to limited test menus and unreliable results. Here we introduce the lightweight, portable Labcorp TrueSpin™ for rapid point-of-care blood separation using commercially available microvolume blood collection tubes. The TrueSpin is a class I FDA-registered device designed for untrained users. The centrifuge runs on AA batteries and separates a blood sample in 5 minutes. Here we describe a series of studies evaluating sample quality and analyte stability in serum samples collected into gel microtubes and processed using the TrueSpin. Hemolysis, residual red blood cell concentration, sample volume, and serum-based chemistry analyte stability were evaluated. No significant difference was seen in hemolysis or residual red blood cell concentration in serum samples prepared by TrueSpin compared to the reference method. Additionally, capillary and venous blood samples separated using the TrueSpin and exposed to International Safe Transit Association 3A-simulated shipping conditions were shown to yield acceptable sample volume and quality for laboratory analysis. Finally, we show that many common serum-based chemistry analytes have limited (< 1 day) stability if uncentrifuged but improve to ≥ 3-day stability following TrueSpin separation and refrigerated or room temperature storage. These findings suggest that the TrueSpin is a simple and effective solution for remote sample separation and may enable broader test menus and increased test result reliability for decentralized sample collection pursuits.

Testosterone identifies hatchling sex for Mojave desert tortoises (Gopherus agassizii)

The threatened Mojave desert tortoise (Gopherus agassizii) exhibits temperature-dependent sex determination, and individuals appear externally sexually monomorphic until sexual maturity. A non-surgical sex identification method that is suitable for a single in situ encounter with hatchlings is essential for minimizing handling of wild animals. We tested (1) whether plasma testosterone quantified by enzyme-linked immunosorbent assay differentiated males from females in 0–3 month old captive hatchlings, and (2) whether an injection of follicle-stimulating hormone (FSH) differentially elevates testosterone in male hatchlings to aid in identifying sex. We validated sex by ceolioscopic (laparoscopic) surgery. We then fit the testosterone concentrations to lognormal distributions and identified the concentration below which individuals are more likely female, and above which individuals are more likely male. Using a parametric bootstrapping procedure, we estimated a 0.01–0.04% misidentification rate for naïve testosterone samples, and a 1.26–1.39% misidentification rate for challenged (post-FSH injection) testosterone samples. Quantification of plasma testosterone concentration from small volume (0.1 mL) blood samples appears to be a viable, highly accurate method to identify sex of 0–3 month old hatchlings and could be a valuable tool for conservation measures and investigation of trends and variation in sex ratios for in situ wild nests.

Irregular Antibody Screening Using a Microdroplet Platform.

The screening procedure for antibodies is considered the most tedious among the three pretransfusion operations, i.e., ABO and Rhesus (Rh) typing, irregular antibody screening/identification, and crossmatching tests. The commonly used screening method for irregular antibodies in clinics at present is a manual polybrene test (MP). The MP test involves numerous reagent replacement and centrifuge procedures, and the sample volume is expected to be relatively less. Herein, screening red blood cells (RBCs) and serum irregular antibodies are encapsulated in microdroplets with a diameter of ~300 μm for a hemagglutination reaction. Owing to the advantage of spatial limitation in microdroplets, screening RBCs and irregular antibodies can be directly agglutinated, thereby eliminating the need for centrifugation and the addition of reagents to promote agglutination, as required by the MP method. Furthermore, the results for a large number of repeated tests can be concurrently obtained, further simplifying the steps of irregular antibody screening and increasing accuracy. Eight irregular antibodies are screened using the proposed platform, and the results are consistent with the MP method. Moreover, the volume of blood samples and antibodies can be reduced to 10 μL and 5 μL, respectively, which is ten times less than that using the MP method.

Trial-related blood sampling and red-blood-cell transfusions in preterm infants.

To determine if trial-related blood sampling increases the risk of later red-blood-cell (RBC) transfusion in very preterm infants, we compared the volume of clinical- and trial-related blood samples, in a specific trial and correlated to subsequent RBC transfusion. For 193 very preterm infants, participating in the FortiColos trial (NCT03537365), trial-related blood volume drawn was in accordance to ethical considerations established by the European Commission. Medical records were reviewed to assess the number and cumulated volume (mL/kg) of blood samples (both clinical- and trial-related). Data were compared with need of RBC transfusions during the first 28days of life. Mean (SD) gestational age and bith weight was 28 ± 1 weeks and 1168 ± 301 g. In total, 11% of total blood volume was drawn for sampling (8.1 ± 5.1 mL/kg) and trial-related sampling accounted for 1.6 ± 0.6 mL/kg. Trial-related blood sampling had no impact on RBC transfusion (p=0.9). Clinical blood sampling in very preterm infants is associated with blood loss and subsequent need for RBC transfusions. In a specific trial requiring blood samples, we found no additional burden of trial-related blood sampling. The study suggest that trial-related sampling is safe if European criteria are followed.

Impact of microsampling on toxicological evaluation in rodent safety studies.

Recently, animal welfare has been attracting worldwide attention, and implementation of 3Rs (replacement, reduction, and refinement) is prioritized in every way possible in the drug development. Microsampling, in which small amounts of blood are collected, is attracting attention in this context. ICH S3A Q&A focused on microsampling was published in November 2017 to help accelerate the application of microsampling for toxicokinetic assessment. The increased sensitivity of drug measurement apparatuses such as mass spectrometers has made it possible to measure drug concentrations with small amounts of blood samples. In this review, we summarized the reports on toxicological influence of microsampling in rodents (rats and mice) with or without drug administration or recovery period after blood collection and influences that may arise from differences in the blood sampling site or blood sampling volume. We also summarized some perspectives on further implementation of microsampling in toxicology studies. The use of microsampling in regulatory toxicology studies has gradually increased, although at a lower rate than in discovery studies. Since more animals are used in GLP toxicology studies than in discovery studies, the effect of reducing the number of animals by microsampling is expected to be greater in the toxicology studies. This report aims to promote the application of microsampling to nonclinical studies, as it is beneficial for improving animal welfare and can contribute to the 3Rs.