This guidance document was prepared on behalf of the International Council for Standardization in Haematology (ICSH) for providing haemostasis-related guidance documents for clinical laboratories. This inaugural coagulation ICSH document was developed by an ad hoc committee, comprised of international clinical and laboratory direct acting oral anticoagulant (DOAC) experts. The committee developed consensus recommendations for laboratory measurement of DOACs (dabigatran, rivaroxaban, apixaban and edoxaban), which would be germane for laboratories assessing DOAC anticoagulation. This guidance document addresses all phases of laboratory DOAC measurements, including pre-analytical (e.g. preferred time sample collection, preferred sample type, sample stability), analytical (gold standard method, screening and quantifying methods) and post analytical (e.g. reporting units, quality assurance). The committee addressed the use and limitations of screening tests such as prothrombin time, activated partial thromboplastin time as well as viscoelastic measurements of clotting blood and point of care methods. Additionally, the committee provided recommendations for the proper validation or verification of performance of laboratory assays prior to implementation for clinical use, and external quality assurance to provide continuous assessment of testing and reporting method.

Hemophilia A is caused by mutations within the Factor VIII (FVIII) gene that lead to depleted protein production and inefficient blood clotting. Several attempts at gene therapy have failed for various reasons-including immune rejection. The recent generation of induced pluripotent stem (iPS) cells from somatic cells by the ectopic expression of 3 transcription factors, Oct4, Sox2, and Klf4, provides a means of circumventing the immune rejection barrier. To date, iPS cells appear to be indistinguishable from ES cells and thus provide tremendous therapeutic potential. Here we prepared murine iPS cells from tail-tip fibroblasts and differentiated them to both endothelial cells and endothelial progenitor cells by using the embryoid body differentiation method. These iPS cells express major ES cell markers such as Oct4, Nanog, SSEA-1, alkaline phosphatase, and SALL4. Endothelial/endothelial progenitor cells derived from iPS cells expressed cell-specific markers such as CD31, CD34, and Flk1 and secreted FVIII protein. These iPS-derived cells were injected directly into the liver of irradiated hemophilia A mice. At various times after transplantation (7-90 days) hemophilia A mice and their control mice counterparts were challenged by a tail-clip bleeding assay. Nontransplanted hemophilia A mice died within a few hours, whereas transplanted mice survived for more than 3 months. Plasma FVIII levels increased in transplanted hemophilia A mice during this period to 8% to 12% of wild type and corrected the hemophilia A phenotype. Our studies provide additional evidence that iPS cell therapy may be able to treat human monogenetic disorders in the future.endothelial cell precursors ͉ Factor VIII ͉ Oct4 ͉ Sox2 ͉ Klf4

Direct oral anticoagulant therapies, including direct anti-Xa and thrombin inhibitors have recently been introduced and may have advantages over vitamin K antagonists such as warfarin. This review describes briefly the clinical utility and mechanism of action of these agents. Detailed information is provided on effect of these agents on routine assays including the APTT and PT as well as their impact on specialty laboratory assays. Also included are the use of drug specific assays and a discussion of alternative methods to determine relative drug concentration, such as evaluating drug calibrators in APTT and PT assays and using heparin calibrated anti-Xa assays to measure direct Xa inhibitors.

In 2018, the International Council for Standardization in Hematology (ICSH) published a consensus document providing guidance for laboratories on measuring direct oral anticoagulants (DOACs). Since that publication, several significant changes related to DOACs have occurred, including the approval of a new DOAC by the Food and Drug Administration, betrixaban, and a specific DOAC reversal agent intended for use when the reversal of anticoagulation with apixaban or rivaroxaban is needed due to life-threatening or uncontrolled bleeding, andexanet alpha. In addition, this ICSH Working Party recognized areas where additional information was warranted, including patient population considerations and updates in point-of-care testing. The information in this manuscript supplements our previous ICSH DOAC laboratory guidance document. The recommendations provided are based on (1) information from peer-reviewed publications about laboratory measurement of DOACs, (2) contributing author’s personal experience/expert opinion and (3) good laboratory practice.

The advent of modern instrumentation, with associated improvements in test reliability, together with appropriate internal quality control and external quality assurance measures, has led to substantial reduction in analytical errors within hemostasis laboratories. Unfortunately, the reporting of incorrect or inappropriate test results still occurs, perhaps even as frequently as in the past. Many of these cases will arise due to a variety of events largely outside the control of the laboratories performing the laboratory tests and primarily comprise preanalytical events related to patient collection and sample processing and postanalytical events related to the reporting and interpretation of test results. The current article provides an overview of these events and provides some suggestions on how they can be minimized or prevented to ensure that the test results the clinician receives actually represent the true clinical status of the patient under investigation rather than just reflecting the status of an (inappropriate) clinical sample received and tested. This article should be of interest to both laboratory scientists working in hemostasis and the clinicians that request such tests. The former, because these are ultimately responsible for the test results they provide to clinicians, and there is a duty of care to provide both accurate and precise results to enable clinicians to manage patients appropriately and to avoid the need to recollect and retest. The latter because unless clinicians gain an appreciation of these issues, they will not be in a position to best manage their patients.

No PT or APTT reagent system effectively detected apixaban. All anti-Xa methods demonstrated sensitivity to low concentrations of DOAC. Dilute viper venom methods are exquisitely sensitive to anti-Xa DOAC, suggesting potential use of this assay for screening or measuring these drugs.

Tumor-associated neoangiogenesis has recently become a suitable target for antineoplastic drug development. In this overview, we discuss specific drug-associated hemostatic complications, the already known pathogenetic mechanisms involved, and the effect of varying antithrombotic strategies. Multiple agents with angiogenic inhibitory capacity (thalidomide, lenalidomide, bevacizumab, sunitinib, sorafenib, and sirolimus) have obtained US Food and Drug Administration approval, and many others have entered clinical trials. Arterial and venous thromboembolism and hemorrhage have emerged as significant toxicities associated with the use of angiogenesis inhibitors. We present a detailed analysis of the literature on thrombotic complication of antiangiogenic drugs. Close attention to hemostatic complications during antiangiogenic treatment is warranted. Further studies are required to better understand the pathophysiologic mechanisms involved and to define a safe prophylactic strategy.

The first direct oral anticoagulant (DOAC) to be approved for clinical use was dabigatran, a direct thrombin inhibitor, in 2010. Since that time, four additional DOACs, all direct anti‐Xa inhibitors, have been approved, including rivaroxaban, apixaban, edoxaban and betrixaban. Our knowledge about the effect of DOACs on laboratory testing, as well as the use of the laboratory for measuring DOACs has been an evolving process. These drugs are not routinely monitored in the same fashion as coumadin, but there is an increasing demand on the laboratory to have the capacity to adequately assess DOAC anticoagulant effect (pharmacodynamics) or levels (pharmacokinetics) in either emergent or the routine situations. This manuscript provides an update on laboratory guidance and progress of methods for measuring DOACs.