Overview of Hemostasis and Thrombosis and Contribution of Laboratory Testing to Diagnosis and Management of Hemostasis and Thrombosis Disorders

Biology and functions of fish thrombocytes: A review

This comprehensive review examines the role of fish thrombocytes, cells considered functionally analogous to platelets in terms of coagulation, but which differ in their origin and morphology. Despite the evolutionary distance between teleosts and mammals, genomic studies reveal conserved patterns in blood coagulation, although there are exceptions such as the absence of factors belonging to the contact system. Beyond coagulation, fish thrombocytes have important immunological functions. These cells express both proinflammatory genes and genes involved in antigen presentation, suggesting a role in both innate and adaptive immune responses. Moreover, having demonstrated their phagocytic abilities, crucial in the fight against pathogenic microorganisms, underscores their multifaceted involvement in immunity. Finally, the need for further research on the functions of these cells is highlighted, in order to better understand their involvement in maintaining the health of aquaculture fish. The use of standardized and automated methods for the analysis of these activities is advocated, emphaiszing their potential to facilitate the early detection of stress or infection, thus minimizing the economic losses that these adverse situations can generate in the field of aquaculture.

Contemporary tools for evaluation of hemostasis in neonates. Where are we and where are we headed?

The assessment of hemostatic disorders in neonates is crucial, but remains challenging for clinicians. Although the concept of developmental hemostasis is widely accepted among hemostasis specialists globally, it is probably under-recognized by clinicians and laboratory practitioners. In parallel with age-dependent hemostatic status maturation, comprehension of the differences between normal values is crucial for the accurate diagnosis of potential hemorrhagic and thrombotic disorders of the vulnerable neonatal population. This review outlines the basics of developmental hemostasis and the features of the available coagulation testing methods, with a focus on novel tools for evaluating the neonatal hemostatic profile. Common errors, issues, and pitfalls during the assessment of neonatal hemostasis are discussed, along with their impact on patient management. Current knowledge gaps and research areas are addressed. Further studying to improve our understanding of developmental hemostasis and its reflection on everyday clinical practice is warranted.

Analysis of laboratory parameters before the occurrence of hepatic sinusoidal obstruction syndrome in children, adolescents, and young adults after hematopoietic stem cell transplantation

PURPOSE

Hepatic sinusoidal obstruction syndrome (SOS) is a serious complication following hematopoietic stem cell transplantation (HSCT) in which early diagnosis improves patient outcome. The aim of our study was to detect laboratory parameters following HSCT that can predict the occurrence of SOS.

METHODS

This retrospective study included 182 children, adolescents, and young adults who underwent allogeneic or autologous HSCT for the first time (median age 7.2 years). The diagnosis of SOS was based on the pediatric criteria of European Society for Blood and Marrow Transplantation (EBMT). We investigated 15 laboratory parameters after HSCT before the onset of SOS.

RESULTS

The overall incidence of SOS was 14.8%. SOS developed in 24 of 126 allogeneic (19.1%) and in 3 of 56 autologous (5.4%) HSCT patients at a median time of 13 days after HSCT. We observed a low SOS mortality rate of 11.1% within 100 days after HSCT. International normalized ratio (INR) ≥ 1.3, activated partial thromboplastin time (aPTT) ≥ 40 s, reptilase time ≥ 18.3 s, factor VIII ≤ 80%, antithrombin III ≤ 75%, protein C ≤ 48%, D-dimer ≥ 315 µg/L, bilirubin ≥ 9 µmol/L, and ferritin ≥ 3100 µg/L showed significant associations with the onset of SOS in the univariate analyses. In the multivariate analysis, INR ≥ 1.3 [odds ratio (OR) = 8.104, p = 0.006], aPTT ≥ 40 s (OR = 10.174, p = 0.001), protein C ≤ 48% (OR = 5.215, p = 0.014), and ferritin ≥ 3100 µg/L (OR = 7.472, p = 0.004) could be confirmed as independent risk factors after HSCT before SOS. If three of the four significant cut-off values were present, the probability of developing SOS was more than 70%. The probability of SOS was 96%, if all four laboratory parameters were changed according to the cut-off values. The values of factor XIII, von Willebrand factor (vWF), von Willebrand factor activity (vWF activity), protein S, fibrinogen, and alanine aminotransferase (ALT) were not relevant for the occurrence of SOS.

CONCLUSION

In summary, the laboratory parameters INR, aPTT, protein C, and ferritin were very useful to predict the occurrence of SOS. In addition, this is the first report on a significant association between SOS and high values of INR and aPTT after HSCT before SOS.

Maternal and Newborn Characteristics-A Comparison between Healthy and Thrombophilic Pregnancy

A thrombophilic woman is more likely to experience difficulties during pregnancy, difficulties that will also affect the development of the newborn. This study aims to compare maternal and newborn characteristics between healthy and thrombophilic pregnancy. The following characteristics were analysed: maternal characteristics (BMI- body mass index, haemostasis parameters, thrombophilia-specific treatment) and newborn characteristics (gestational period, birth weight, the Apgar score). This follow-up study spanning five years, from 2018 to 2022, focuses on a cohort of 500 women who underwent delivery hospitalization in the western region of Romania. The maternal characteristics influence the newborn: the greater the weight of the mother with thrombophilia, the more the chances that the fetus will have a lower birth weight; increasing the dose of LMWH (low molecular weight heparin), connected with the necessity to control the homeostasis parameters, the more likely the fetus will be born with a lower birth weight. A pregnant woman with thrombophilia, treated appropriately, having a normal weight, and not presenting other risk factors independent of thrombophilia, will have a newborn with characteristics similar to a healthy pregnant woman.

Designing Synthetic, Sulfated Glycosaminoglycan Mimetics That Are Orally Bioavailable and Exhibiting In Vivo Anticancer Activity

Sulfated glycosaminoglycans (GAGs), or synthetic mimetics thereof, are not favorably viewed as orally bioavailable drugs owing to their high number of anionic sulfate groups. Devising an approach for oral delivery of such highly sulfated molecules would be very useful. This work presents the concept that conjugating cholesterol to synthetic sulfated GAG mimetics enables oral delivery. A focused library of sulfated GAG mimetics was synthesized and found to inhibit the growth of a colorectal cancer cell line under spheroid conditions with a wide range of potencies ( 0.8 to 46 μM). Specific analogues containing cholesterol, either alone or in combination with clinical utilized drugs, exhibited pronounced in vivo anticancer potential with intraperitoneal as well as oral administration, as assessed by ex vivo tertiary and quaternary spheroid growth, cancer stem cell (CSC) markers, and/or self-renewal factors. Overall, cholesterol derivatization of highly sulfated GAG mimetics affords an excellent approach for engineering oral activity.

Hemostasis and Thrombosis: An Overview Focusing on Associated Laboratory Testing to Diagnose and Help Manage Related Disorders

Hemostasis is a complex but balanced process that permit normal blood flow, without adverse events. Disruption of the balance may lead to bleeding or thrombotic events, and clinical interventions may be required. Hemostasis laboratories typically offer an array of tests, including routine coagulation and specialized hemostasis assays used to guide clinicians for diagnosing and managing patients. Routine assays may be used to screen patients for hemostasis-related disturbances but may also be used for drug monitoring, measuring efficacy of replacement or adjunctive therapy, and other indications, which may then be used to guide further patient management. Similarly, "specialized" assays are used for diagnostic purposes or may be used to monitor or measure efficacy of a given therapy. This chapter provides an overview of hemostasis and thrombosis, with a focus on laboratory testing that may be used to diagnose and help manage patients suspected of hemostasis- and thrombosis-related disorders.

Auto-validation of Routine Coagulation/Hemostasis Assays with Reflex Testing of Abnormal Test Results

Hemostasis laboratories play a crucial role in the diagnosis and treatment of individuals with bleeding or thrombotic disorders. Routine coagulation assays, including the prothrombin time (PT)/international normalized ratio (INR), and activated partial thromboplastin time (APTT), are used for various purposes. These include as a screen of hemostasis function/dysfunction (e.g., possible factor deficiency) and for monitoring of anticoagulant therapy, such as vitamin K antagonists (PT/INR) and unfractionated heparin (APTT). Clinical laboratories are also under increasing pressure to improve services, especially response (test turnaround) times. There is also a need for laboratories to try to reduce error rates and for laboratory networks to standardize/harmonize processes and policies. Accordingly, we describe our experience with the development and implementation of automated processes for reflex testing and validation of routine coagulation test results. This has been implemented in a large pathology network compromising 27 laboratories and is under consideration for expansion to our larger network (of 60 laboratories). These rules have been custom-built within our laboratory information system (LIS), perform reflex testing of abnormal results, and fully automate the process of routine test validation for appropriate results. These rules also permit adherence to standardized pre-analytical (sample integrity) checks, automate reflex decisions, automate verification, and provide an overall alignment of network practices in a large network of 27 laboratories. In addition, the rules enable clinically significant results to be quickly referred to hematopathologists for review. We also documented an improvement in test turnaround times, with savings in operator time and thus operating costs. Finally, the process was generally well received and determined to be beneficial for most laboratories in our network, in part identified by improved test turnaround times.

Evaluation of the Analytical Performances of the Biolabo SOLEA 100 Optical Coagulometer and Comparison with the Stago STA-R MAX Analyser in the Determination of PT, APTT, and Fibrinogen

INTRODUCTION

The Biolabo Solea 100 is a fully automated coagulation analyser using an optical system to detect coagulation designed to meet the needs of small- and medium-sized laboratories. This study aimed to evaluate the analytical performance in terms of bias, precision, and interference of the Biolabo Solea 100 coagulometer under routine laboratory conditions. In addition, a comparison was made with Stago STA-R MAX.

MATERIALS AND METHODS

Imprecision and bias were evaluated for activated partial thromboplastin time (APTT), fibrinogen (FIB), and prothrombin time (PT) at the medical decision levels. The results of 200, 181, and 206 plasma samples for APTT, FIB, and PT, respectively, were compared with those obtained by Stago STA-R MAX. In addition, the interference level of bilirubin, haemoglobin, triglycerides, and fractionated heparin was evaluated.

RESULTS

Repeatability, intermediate imprecision, bias, and total error are overall below the defined limits of acceptability. Of interest is the high degree of agreement between Solea 100 and STA-R MAX with respect to PT (s), which fits perfectly with the theoretical line of identity (y = 0 + 1.00x). No interferences were found within the limits stated by the manufacturer, with some exceptions for APTT with heparin and APTT and PT for higher bilirubin concentrations.

CONCLUSIONS

In conclusion, the performance of the Solea 100 optical analyser is satisfactory and adequate for the determination of routine coagulation tests. Moreover, they are perfectly comparable to mechanical systems, such as STA-R MAX and other upper-level analysers, even considering the low interference levels under routine conditions.

Platelets, Macrophages, and Thromboinflammation in Chagas Disease

Chagas disease (CD) is a major health problem in the Americas and an emerging health problem in Europe and other nonendemic countries. Several studies have documented persistence of the protozoan parasite Trypanosoma cruzi, and oxidative and inflammatory stress are major pathogenic factor. Mural and cardiac thrombi, cardiac arrhythmias, and cardiomyopathy are major clinical features of CD. During T. cruzi infection, parasite-released factors induce endothelial dysfunction along with platelet (PLT) and immune-cell activation. PLTs have a fundamental role in maintaining hemostasis and preventing bleeding after vascular injury. Excessive activation of PLTs and coagulation cascade can result in thrombosis and thromboembolic events, which are recognized to occur in seropositive individuals in early stages of CD when clinically symptomatic heart disease is not apparent. Several host and parasite factors have been identified to signal hypercoagulability and increase the risk of ischemic stroke in early phases of CD. Further, PLT interaction with immune cells and their role in host defense against pathogens and inflammatory processes have only recently been recognized and evolving. In the context of parasitic diseases, PLTs function in directly responding to T. cruzi infection, and PLT interactions with immune cells in shaping the proinflammatory or immunoregulatory function of monocytes, macrophages, and neutrophils remains elusive. How T. cruzi infection alters systemic microenvironment conditions to influence PLT and immune-cell interactions is not understood. In this review, we discuss the current literature, and extrapolate the mechanistic situations to explain how PLT and innate immune cell (especially monocytes and macrophages) interactions might be sustaining hypercoagulability and thromboinflammation in chronic CD.

Pathophysiology of Coagulation and Emerging Roles for Extracellular Vesicles in Coagulation Cascades and Disorders

The notion of blood coagulation dates back to the ancient Greek civilization. However, the emergence of innovative scientific discoveries that started in the seventeenth century formulated the fundamentals of blood coagulation. Our understanding of key coagulation processes continues to evolve, as novel homeostatic and pathophysiological aspects of hemostasis are revealed. Hemostasis is a dynamic physiological process, which stops bleeding at the site of injury while maintaining normal blood flow within the body. Intrinsic and extrinsic coagulation pathways culminate in the homeostatic cessation of blood loss, through the sequential activation of the coagulation factors. Recently, the cell-based theory, which combines these two pathways, along with newly discovered mechanisms, emerged to holistically describe intricate in vivo coagulation mechanisms. The complexity of these mechanisms becomes evident in coagulation diseases such as hemophilia, Von Willebrand disease, thrombophilia, and vitamin K deficiency, in which excessive bleeding, thrombosis, or unnecessary clotting, drive the development and progression of diseases. Accumulating evidence implicates cell-derived and platelet-derived extracellular vesicles (EVs), which comprise microvesicles (MVs), exosomes, and apoptotic bodies, in the modulation of the coagulation cascade in hemostasis and thrombosis. As these EVs are associated with intercellular communication, molecular recycling, and metastatic niche creation, emerging evidence explores EVs as valuable diagnostic and therapeutic approaches in thrombotic and prothrombotic diseases.

Harmonizing factor assay-related testing performed in a large laboratory network

Coagulation factor testing is commonly performed within haemostasis laboratories, either to assess for bleeding disorders, such as haemophilia, or to investigate unexplained prolongation in routine coagulation assays. The aim of this evaluation was to harmonize procedures and normal reference ranges (NRRs) for investigation of coagulation factors on the ACL TOP 50 family of instruments in a large laboratory network. We employed comparative evaluations using newly installed ACL TOPs 550 and 750 and HemosIL reagents vs. existing 'reference' instrumentation and reagents, predominantly Stago and Siemens, as well as assessment of factor sensitivity in routine coagulation assays, prothrombin time (PT) and activated partial thromboplastin time (APTT). Also, establishment of coagulation factor NRRs using normal plasma samples. HemosIL factor assays showed good comparability with the existing reference methods (R > 0.9). Factor sensitivity for PT and APTT assays were acceptable at around 30 U/dl. NRRs were established and harmonized across the laboratory network. This evaluation of factor testing on ACL TOP 50 Family instruments identified overall acceptable performance using Werfen reagents and enabled harmonization of coagulation factor testing in our large network.

Coumarin Derivatives Inhibit ADP-Induced Platelet Activation and Aggregation

Coumarin was first discovered in Tonka bean and then widely in other plants. Coumarin has an anticoagulant effect, and its derivative, warfarin, is a vitamin K analogue that inhibits the synthesis of clotting factors and is more widely used in the clinical treatment of endovascular embolism. At present, many artificial chemical synthesis methods can be used to modify the structure of coumarin to develop many effective drugs with low toxicity. In this study, we investigated the effects of six coumarin derivatives on the platelet aggregation induced by adenosine diphosphate (ADP). We found that the six coumarin derivatives inhibited the active form of GPIIb/IIIa on platelets and hence inhibit platelet aggregation. We found that 7-hydroxy-3-phenyl 4H-chromen-4-one (7-hydroxyflavone) had the most severe effect. In addition, we further analyzed the downstream signal transduction of the ADP receptor, including the release of calcium ions and the regulation of cAMP, which were inhibited by the six coumarin derivatives selected in this study. These results suggest that coumarin derivatives inhibit coagulation by inhibiting the synthesis of coagulation factors and they may also inhibit platelet aggregation.

Anticoagulants and the Hemostatic System: A Primer for Occupational Stress Researchers

Anticoagulation, the body’s mechanism to prevent blood clotting, is an internal biomarker of an individual’s response to stress. Research has indicated that understanding the causes, processes, and consequences of anticoagulation can provide important insight into the experience of individuals facing emotional and occupational strain. Unfortunately, despite their importance, the mechanisms and implications of anticoagulation are unfamiliar to many researchers and practitioners working with trauma-exposed professionals. This paper provides an accessible primer on the topic of anticoagulation, including an overview of the biological process, the research connecting these processes with emotional and occupational functioning, as well as some potential methods for assessment.

Determining the Optimal Storage Time and Temperature for Performing Platelet Function Assays and Global Hemostasis Assays

Platelet function assays and global haemostasis assays are essential in diagnosing bleeding tendencies, with light transmission aggregometry (LTA) as golden standard. The Multiple Electrode Aggregation (Multiplate), platelet function assay (PFA) and rotational thromboelastometry (ROTEM) are mostly used as whole-blood screening tests. Currently, patients have to travel to specialized laboratories to undergo these tests, since specific expertise is required. Pre-analytical variables, like storage time and temperature during transport, are still considered to be the most vulnerable part of the process and may lead to discrepancies in the test results. We aim to give a first impression on the stability of blood samples from healthy volunteers during storage and investigate the effect of storage time (1, 3, 6 and 24 hours) and temperature (4°C, room temperature and 37°C) on the Multiplate, PFA, ROTEM and LTA test results. Our data indicated that, for the PFA, whole blood can be stored for 3 hours at room temperature. Whole blood used for the Multiplate and ROTEM can be stored for 6 hours of storage. For LTA, PRP and whole blood were stable up to 3 hours at 4°C or room temperature and 6 hours at room temperature, respectively.

Preemptive intravenous iron therapy versus autologous whole blood therapy for early postoperative hemoglobin level in patients undergoing bimaxillary orthognathic surgery: a prospective randomized noninferiority trial

BACKGROUND

Previous studies have reported the efficacy and safety of intravenous (IV) iron therapy during the perioperative period as an alternative and adjunct to allogeneic blood transfusion. Preemptive IV iron therapy provides noninferior hemoglobin levels on postoperative day (POD) 1 compared to autologous whole blood therapy (AWBT) in healthy patients who had undergone bimaxillary orthognathic surgery.

METHODS

This was a prospective, patient-randomized, noninferiority trial. After excluding 2 patients, 64 patients were divided into two groups: the IV iron therapy group (patients received IV iron infusion 4 weeks before surgery; n = 32) and the AWBT group (2 units of autologous whole blood were collected 4 and 2 weeks before surgery; n = 32). The primary outcome was hemoglobin level on POD 1 and the prespecified noninferiority limit was - 1 g/dL.

RESULTS

Baseline data were comparable, including hemoglobin and iron levels, between the two groups. Immediately before surgery, the levels of hemoglobin, iron, and ferritin were higher in the IV iron group than in the AWBT group. The mean treatment difference (iron group-whole blood group) in hemoglobin level on POD 1 between the two groups was 0.09 (95% CI = - 0.83 to 1.0). As the lower limit of the 95% CI (- 0.83) was higher than the prespecified noninferiority margin (δ = - 1), noninferiority was established. On POD 2, the hemoglobin level became lower in the iron group, which eventually led to greater requirement of allogeneic blood transfusion compared to the whole blood group. However, the iron group did not require allogeneic blood transfusion during or early after surgery, and the whole blood group showed continuously higher incidence of overt iron deficiency compared to the iron group.

CONCLUSION

As collection of autologous whole blood caused overt iron loss and anemia before surgery and intraoperative transfusion of whole blood was not able to prevent the occurrence of persistent iron deficiency after surgery, IV iron therapy was found to have potential benefits for iron homeostasis and subsequent erythropoiesis in healthy patients early after bimaxillary orthognathic surgery.

TRIAL REGISTRATION

Clinical Research Information Service, Republic of Korea, approval number: KCT0003680 on March 27, 2019. https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=15769&sLeft=2&ltype=my&rtype=my .

Shedding Light on the Role of Extracellular Vesicles in HIV Infection and Wound Healing

Extracellular vesicles (EVs) play an important role in intercellular communication. They are naturally released from cells into the extracellular environment. Based on their biogenesis, release pathways, size, content, and function, EVs are classified into exosomes, microvesicles (MVs), and apoptotic bodies (ApoBDs). Previous research has documented that EVs, specifically exosomes and MVs, play an important role in HIV infection, either by promoting HIV infection and pathogenesis or by inhibiting HIV-1 to a certain extent. We have also previously reported that EVs (particularly exosomes) from vaginal fluids inhibit HIV at the post-entry step (i.e., reverse transcription, integration). Besides the role that EVs play in HIV, they are also known to regulate the process of wound healing by regulating both the immune and inflammatory responses. It is noted that during the advanced stages of HIV infection, patients are at greater risk of wound-healing and wound-related complications. Despite ongoing research, the data on the actual effects of EVs in HIV infection and wound healing are still premature. This review aimed to update the current knowledge about the roles of EVs in regulating HIV pathogenesis and wound healing. Additionally, we highlighted several avenues of EV involvement in the process of wound healing, including coagulation, inflammation, proliferation, and extracellular matrix remodeling. Understanding the role of EVs in HIV infection and wound healing could significantly contribute to the development of new and potent antiviral therapeutic strategies and approaches to resolve impaired wounds in HIV patients.

Understanding the "philosophy" of laboratory hemostasis

Unlike many other areas of laboratory medicine, laboratory hemostasis has some peculiarities, which makes it one of the most complex diagnostic domains in clinical medicine. The inherent complexity of the hemostasis process, the components of which have not yet been thoroughly unravelled, is mirrored by a large number of hemostasis disturbances, which can involve single or multiple components. Although laboratory diagnostics represents an unavoidable part of the diagnostic reasoning in patients with bleeding or thrombotic disorders, the basic concept beneath the assumption that in many human pathologies, one single test may be sufficient for the diagnosis, does not hold true in hemostasis. There are in fact many aspects that would lead us to conclude that laboratory hemostasis can be considered a very challenging arena for many clinicians and perhaps also for some laboratory professionals. The most challenging aspects typically include the following concepts; that hemostasis is an intricate and multifaceted process, that more than one test is typically needed to achieve a final diagnosis, that results of screening tests depend on many biological factors and do not allow making a final diagnosis, that harmonization of techniques is still an unmet target, and that the calculations used vary widely among laboratories. This article is hence aimed at discussing many of these aspects, with the hope of presenting a useful contribution to better understand the "philosophy" of laboratory hemostasis.

Simple Laboratory Test Utilization Interventions to Reduce Inappropriate Specialty Coagulation Testing

OBJECTIVES

The naming convention in coagulation may cause confusion in electronic ordering systems, leading to inappropriate test orders. We implemented test utilization efforts and studied utilization before and after interventions for two specialty coagulation assays.

METHODS

Two interventions were implemented: test names were changed from factor assay to activity, and residents reviewed all factor V and X requests. A retrospective review of factor V and X activity orders was performed for the period 1 year before and after interventions.

RESULTS

After interventions, factor V and X activity orders decreased by approximately 40%. Resulted tests decreased by 53.8% and 47.8%, corresponding to reductions of $2,493.05 and $1,867.80 per year in laboratory charges for factor V and factor X activity, respectively. Abnormal factor V activity results increased from 45% to 59%. Factor V activity orders from outpatient clinics decreased by 21.6%.

CONCLUSIONS

Simple interventions can reduce inappropriate specialty coagulation test orders and unnecessary costs.

Coagulation mixing studies: Utility, algorithmic strategies and limitations for lupus anticoagulant testing or follow up of abnormal coagulation tests

Coagulation testing underpins the investigation of hemostasis and/or monitoring of anticoagulation therapy for prevention and/or treatment of thrombosis related pathology. Assessment of coagulation results requires comparison against a normal reference range or interval (NRR/NRI). Results flagged as "abnormal" (ie, above the NRR/NRI for patients not on anticoagulant therapy), typically require further evaluation. eg, follow up or reflexive testing is used to identify the reason for prolongation, especially when supported by clinical context (eg, bleeding). Mixing tests may have utility to help identify the pathway of follow-up testing (ie, towards investigation of factor deficiencies, or else inhibitors), and are also useful for investigation of lupus anticoagulants (LA). In general, mixing tests that "correct" tend to suggest the presence of factor deficiencies, where as those that do not correct suggest the presence of "inhibitors". Various approaches can be used to identify correction/non-correction, and all have strengths and limitations. Furthermore, eventual identification of causal factor deficiencies or even "inhibitors" may (eg, factor VIII or IX deficiencies or inhibitors) or may not (eg, factor XII deficiency) be clinically important. Ultimately, mixing studies performed in view of appropriate clinical scenarios (eg, bleeding patient) and for LA investigations in symptomatic patients will have best utility.

Establishing a reference range for thromboelastography maximum amplitude in patients administrating with antiplatelet drugs

Objective

We aimed to establish the reference range of thromboelastograph (TEG) maximum amplitude (MA) in patients taking antiplatelet drugs.

Methods

Between August 2015 and July 2018, a total of 4614 patients administrating with antiplatelet drugs (clopidogrel and aspirin) were retrospectively analyzed in this study. For MA_A parameter, we used the 10th and 90th percentiles to establish a reference range. The Spearman correlation was used for the correlation analysis among the inhibition rate of adenosine diphosphate (ADP%) and MA_ADP, inhibition rate of arachidonic acid (AA%) and MA_AA. Then, through receiver operating characteristic (ROC) curve analysis of the best cutoff point, the reference ranges of MA_ADP and MA_AA could be deduced. Consistency evaluation was performed by statistical analysis of ADP% and MA_ADP, AA% and MA_AA pairing for 4459 patients.

Results

The reference range of MA_A was 8.1‐25.8 mm. The reference range of MA_ADP was 19.8‐43.2 mm, and the corresponding sensitivity of two endpoints was 0.796, 0.856 and specificity were 0.897, 0.904, respectively. The reference range of MA_AA was 18.9‐37.7 mm, and the corresponding sensitivity of two endpoints was 0.819, 0.829 and specificity were 0.922, 0.896, respectively. The inconsistency rate of ADP% and MA_ADP, and AA% and MA_AA was 20.1% (898 cases) and 16.6% (738 cases), respectively.

Conclusions

The reference range of MA_ADP and MA_AA established by us were better in sensitivity and specificity. MA_ADP and MA_AA were more accurate than conventional inhibition rate analysis in guidance of antiplatelet therapy, especially in patients with excessive low MA or high MA_A.

Evaluation of the Atellica COAG 360 coagulation analyzer in a central laboratory of a maximum care hospital

INTRODUCTION

Fully-automated coagulation analyzers are key components of a high-throughput central laboratory. The novel Atellica COAG 360 (Siemens Healthineers) is a high-volume coagulation analyzer approved for hemostasis diagnostics. The aim of the study was to evaluate the analytical performance of this coagulation analyzer in a central laboratory.

METHODS

Intra (n = 10)- and inter (n = 20)-assay precision of the Atellica COAG 360 was determined using commercially available control samples. Patient samples (n = 74-104) were used for comparison analyses with the Sysmex CS-5100 (Siemens Healthineers). Effects of visual interferences on coagulation testing were assessed and the sample throughput rate of the Atellica COAG 360 was determined.

RESULTS

Intra- and inter-assay precision of the Atellica COAG 360 showed coefficient of variations (CVs) < 5% for most of the coagulation parameters comparable to CVs of the Sysmex CS-5100. Passing-Bablok and Bland-Altman analyses revealed high correlation and good agreement between both coagulation analyzers in determination of coagulation parameters. Results of coagulation measurements determined in optically abnormal samples were comparable between the Atellica COAG 360 and the Sysmex CS-5100 and were confirmed by mechanical measurements on a STart Max (Stago Diagnostics) coagulation analyzer. A sample throughput rate of about 190 tests per hour in a routine setting including five coagulation parameters was determined for the Atellica COAG 360 integrated in a total laboratory automation system.

CONCLUSION

The Atellica COAG 360 provides high analytical performance as high-throughput analyzer for routine and specific coagulation parameters and is suitable to be connected to a total laboratory automation.

Biofabrication of thick vascularized neo-pedicle flaps for reconstructive surgery

Wound chronicity due to intrinsic and extrinsic factors perturbs adequate lesion closure and reestablishment of the protective skin barrier. Immediate and proper care of chronic wounds is necessary for a swift recovery and a reduction of patient vulnerability to infection. Advanced therapies supplemented with standard wound care procedures have been clinically implemented to restore aberrant tissue; however, these treatments are ineffective if local vasculature is too compromised to support minimally-invasive strategies. Autologous "flaps", which are tissues equipped with their own hierarchical vascular supply, can be harvested from one region of the patient and transplanted to the wound where it is reperfused upon microsurgical anastomosis to appropriate recipient vessels. Despite the success of autologous flap transfer, these procedures are extremely invasive, incur obligatory donor-site morbidity, and require sufficient donor-tissue availability, microsurgical expertise, and specialized equipment. 3D-bioprinting modalities, such as extrusion-based bioprinting, can be used to address the clinical constraints of autologous flap transfer, primarily addressing donor-site morbidity and tissue availability. This advancement in regenerative medicine allows the biofabrication of heterogeneous tissue structures with high shape fidelity and spatial resolution to generate biomimetic constructs with the anatomically-precise geometries of native tissue to ensure tissue-specific function. Yet, meaningful progress toward this clinical application has been limited by the lack of vascularization required to meet the nutrient and oxygen demands of clinically relevant tissue volumes. Thus, various criteria for the fabrication of functional tissues with hierarchical, patent vasculature must be considered when implementing 3D-bioprinting technologies for deep, chronic wounds.

An abrupt rise of coagulation error messages on ACL TOP automated analysers

Introduction

Blood coagulation tests (BCT) are very important for clinicians to diagnose bleeding or thrombotic disorders and to monitor anticoagulant therapy.

Case description

On a Saturday morning, a laboratory technician noted an abrupt rise in the number of coagulation error messages on our ALC TOP analysers. Visual inspection revealed the presence of partially and/or fully clotted citrate tubes and prompted the clinical biologist to further investigate a potential preanalytical cause.

Considered causes

Partially or fully clotted blood in citrate tubes can have multiple causes including improper mixing of the tube, under- or overfilling or combining blood samples from different tubes into one citrate tube.

What happened

The affected citrate tubes originated mostly from the same clinical departments. Moreover, all the affected tubes shared the same lot number (1 of 7 in use at the time). Visual inspection of 7 unopened boxes of 100 citrate tubes of this lot number revealed one box with nine completely empty and two partially filled tubes and one box with two partially filled tubes. No under-filled tubes were found in the other 5 boxes.

Discussion

The blood to additive ratio is crucial for BCT. A sudden rise in clot errors should trigger a thorough investigation to identify the cause.

Main lesson

Laboratories should regularly monitor and evaluate the percentage of clotted samples as a quality indicator at scheduled time points. A problem with the volume of additive in citrate tubes should be considered as a possible cause.

Establishing a reference range for thromboelastograph parameters in the neonatal period

Introduction

Acquired coagulation disorders are a common cause of neonatal bleeding. The thromboelastograph (TEG) comprehensively assesses haemostatic processes in the body. Unfortunately, the reference range of TEG parameters in the neonatal period has not yet been evaluated, which limits the use of the TEG in neonates. In this study, we aimed to establish the reference range of TEG parameters for the neonatal period.

Methods

This study included 371 full‐term infants (≥37 weeks of gestation), and we divided these infants into three groups according to age as follows: 1, 2‐7 and 8‐28 days. We measured their peripheral blood using TEG, coagulation routine and platelet count tests. We analysed differences among the groups.

Results

The reference ranges for TEG parameters are presented as medians and reference ranges (2.5th and 97.5th percentiles) as follows: R (clot reaction time, seconds) 4.80 (2.80‐7.17), Angle (fibrin production rate) 69.90 (44.91‐78.89), K (clot kinetics, min) 1.40 (0.80‐4.50), MA (maximum amplitude, mm) 63.50(44.34‐74.66) and LY30 (lysis at 30 minutes, %) 0.10 (0.10‐6.95). There were significant differences in Angle, K, MA and LY30 values between the different neonatal day age groups.

Conclusion

This study preliminarily establishes a reference range for TEG parameters during the neonatal period. The age of a newborn had a large influence on TEG parameters. Additionally, we demonstrated a correlation between laboratory tests and TEG parameters for this age period. The reference values provided herein are meaningful for future studies.

Laboratory hemostasis: from biology to the bench

Physiological hemostasis is an intricate biological system, where procoagulant and anticoagulant forces interplay and preserves blood fluidity when blood vessels are intact, or trigger clot formation to prevent excessive bleeding when blood vessels are injured. The modern model of hemostasis is divided into two principal phases. The first, defined as primary hemostasis, involves the platelet-vessel interplay, whilst the second, defined as secondary hemostasis, mainly involves coagulation factors, damaged cells and platelet surfaces, where the so-called coagulation cascade rapidly develops. The activation and amplification of the coagulation cascade is finely modulated by the activity of several physiological inhibitors. Once bleeding has been efficiently stopped by blood clot formation, dissolution of the thrombus is essential to restore vessel permeability. This process, known as fibrinolysis, also develops through coordinate action of a vast array of proteins and enzymes. An accurate diagnosis of hemostasis disturbance entails a multifaceted approach, encompassing family and personal history of hemostatic disorders, accurate collection of clinical signs and symptoms, integrated with laboratory hemostasis testing. Regarding laboratory testing, a reasonable approach entails classifying hemostasis testing according to cost, complexity and available clinical information. Laboratory workout may hence initiate with some rapid and inexpensive "screening" tests, characterized by high negative predictive value, then followed by second- or third-line analyses, specifically aimed to clarify the nature and severity of bleeding or thrombotic phenotype. This article aims to provide a general overview of the hemostatic process, and to provide some general suggestions to optimally facilitate laboratory hemostasis testing.

Postanalytical considerations that may improve the diagnosis or exclusion of haemophilia and von Willebrand disease

von Willebrand disease (VWD) and haemophilia represent the most common inherited or acquired bleeding disorders. However, many laboratories and clinicians may be challenged by their accurate diagnosis or exclusion. Difficulties in diagnosis/exclusion may include analytical issues, where assays occasionally generate an incorrect result (ie representing an analytical error) or have limitations in their measurement range of and/or low analytical sensitivity. Also increasingly recognized is the influence of preanalytical issues on the diagnosis of VWD or haemophilia. Unfortunately, postanalytical considerations are often not well considered in the diagnostic process. Therefore, this narrative review aims to provide an overview of some important postanalytical considerations that may help improve the diagnosis of VWD and haemophilia. This review primarily discusses aspects around reporting of test results. However, we also discuss other less well-recognized postanalytical considerations, including the use of assay ratios to help identify differential diagnoses and then guide further investigation.

An update on quality control for the PFA-100/PFA-200

Testing of platelet function comprises a crucial element of hemostasis assessment, particularly for investigations into bleeding and/or bruising. The Platelet Function Analyzer (PFA)-100 is the most utilized primary hemostasis-screening test system available, as recently remodeled/upgraded to the PFA-200. Internal quality control (IQC) and external quality assessment (EQA) (including proficiency testing) represent critical elements of ensuring test practice quality. Although true for all tests, IQC and EQA are logistically challenging for platelet function testing, inclusive of the PFA-100/200. We accordingly update our experience with novel yet feasible approaches to both IQC and EQA of PFA-100/200. Over the past 10 years, a total of 43 challenges have been tested, with most challenges designed to mimic moderate or severe primary hemostasis defects. The current report is restricted to the last four years and has also differentially assessed PFA-100 vs. PFA-200 EQA results to identify potential variance. Numerical results for closure times (CTs) and participant-supplied interpretive comments were analyzed. Reported CTs for each challenge were within limits of expectation, and good reproducibility was evidenced by repeated challenges. Coefficients of variation (CVs) for challenges, generally ranging from 15% to 25%, were similar or better than those obtained using native whole blood and consistent with past reports. Participant interpretations were generally consistent with test data and expectations. There was no evident difference in PFA-100 vs. PFA-200 EQA test results. The EQA material has also been successfully evaluated from the perspective of potential IQC. To conclude, IQC and EQA processes for the PFA-100/200 have been established that are highly reproducible, supporting the concept of EQA/IQC for platelet function testing, and also facilitating monitoring and improvement in its performance. In terms of EQA, PFA-100 and PFA-200 instruments appear to behave similarly.