Handheld Point-of-Care Devices for Snakebite Coagulopathy: A Scoping Review.

Venom-induced consumption coagulopathy (VICC) is a common complication of snakebite that is associated with hypofibrinogenemia, bleeding, disability, and death. In remote tropical settings, where most snakebites occur, the 20-minute whole blood clotting test is used to diagnose VICC. Point-of-care (POC) coagulation devices could provide an accessible means of detecting VICC that is better standardized, quantifiable, and more accurate.

Pre-analytical variables in haemostasis: Findings from the United Kingdom National External Quality Assessment scheme for Blood Coagulation (UK NEQAS BC) haemolysis exercise.

Introduction: Haemolysis is considered one of the major contributors of nonconformities and sample rejection in coagulation testing.

Materials And Methods: Two lyophilized plasmas were distributed to 800 centres registered for prothrombin time (PT), activated partial thromboplastin time (APTT) and either Clauss fibrinogen or thrombin time (TT) in the UK NEQAS BC programme. The same pool of normal plasma was used to prepare both samples, to one of which red blood cell haemolysate was added to mimic haemolysis at 3 g/L haemoglobin concentration.

Effects of Emicizumab on APTT, FVIII assays and FVIII Inhibitor assays using different reagents: Results of a UK NEQAS proficiency testing exercise.

Introduction: Emicizumab (Hemlibra: Roche Switzerland) is a, humanized, bi-specific monoclonal modified immunoglobulin G4 (IgG4) which binds human FX, FIX and activated FIX (FIXa) to mimic activated FVIII activity.

Aim: Evaluate the effects of emicizumab on the APTT, surrogate FVIII activity and FVIII inhibitor results.

Methods: Two samples were provided, one obtained from an emicizumab treated severe haemophilia A patient with FVIII inhibitors and one constructed by in vitro addition of emicizumab using plasma from a severe haemophilia A patient without FVIII inhibitors.

Clotting and chromogenic factor VIII assay variability in post-infusion and spiked samples containing full-length recombinant FVIII or recombinant factor VIII Fc fusion protein (rFVIIIFc).

Introduction: Variability in FVIII measurement is a recognized problem. There are limited data for samples containing recombinant Factor VIII Fc fusion protein (rFVIIIFc). Many studies use samples for which factor concentrate has been spiked into FVIII deficient plasma in vitro.

The importance of commutability in material used for quality control purposes.

External Quality Assessment (EQA) is an important part of laboratory quality assurance. Spiking of normal plasma is sometimes employed to mimic clinical samples. It is important that spiked material gives similar results to clinical samples (ie, is commutable) to ensure appropriate conclusions can be drawn from EQA exercises.

Bridging the gap between point-of-care testing and laboratory testing in hemostasis.

Point-of-care (POC) testing within hemostasis is an expanding field, with the most widely used test being POC international normalized ratio (INR). Many of these devices are being used in a nonlaboratory setting by staff with no laboratory training. In the United Kingdom, external quality assessment (EQA) is provided by the organization UK National External Quality Assessment Scheme for Blood Coagulation (UK NEQAS BC).

Problems and solutions in laboratory testing for hemophilia.

A diagnosis of hemophilia A or hemophilia B begins with clinical assessment of the patient and is facilitated by laboratory testing. The influence of the latter on a diagnosis of hemophilia A or hemophilia B is clear-a diagnosis cannot be made without laboratory confirmation of a deficiency of factor FVIII (FVIII) or factor IX (FIX), respectively. Moreover, the degree of hemophilia severity is specifically characterized by laboratory test results.

Point of Care INR testing devices: performance of the Roche CoaguChek XS and XS Plus in the UK NEQAS BC external quality assessment programme for healthcare professionals: four years' experience.

Background: Vitamin K antagonists have been used for many decades and have been traditionally monitored by the measurement of the International Normalised Ratio (INR) in the laboratory. Introduction of Point of Care (POC) testing devices to measure INR has resulted in many tests being undertaken in primary care. External Quality Assessment (EQA) of these POC devices is recommended to ensure accuracy and reliability of INR results outside a laboratory setting.

Interpretation and management of INR results: a case history based survey in 13 countries.

Introduction: Standardisation of treatment with vitamin K antagonists (VKAs) is still an issue after 60 years of use. The study aimed to explore aspects of VKA monitoring in primary and secondary care.

Methods: Two case histories were distributed to physicians in 13 countries.

External quality assessment of point-of-care International Normalized Ratio (INR) testing in Europe.

Background: Point-of-care testing (POCT) of prothrombin time, expressed as International Normalized Ratio (INR), is widely used to monitor patients in oral anticoagulation treatment. Guidelines recommend that POCT users should participate in an external quality assessment (EQA) scheme whenever available. The aim of this study was to investigate which European countries provide EQA for POCT INR and to compare how these schemes are organized.

Quality assurance and quality control of thrombelastography and rotational Thromboelastometry: the UK NEQAS for blood coagulation experience.

Global hemostasis devices are currently being employed in operating rooms to assess the bleeding risk and outcomes for patients undergoing surgery. Two devices currently available are the TEG (Thromboelastograph; Haemoscope Corp., Niles, IL) and the ROTEM (Rotation Thromboelastometer; Pentapharm GmbH, Munich, Germany).

Interlaboratory variation in factor VIII:C inhibitor assay results is sufficient to influence patient management: data from the UK national quality external assessment scheme for blood coagulation.

We report the results of external quality assessment exercises in which 60 to 120 centers performed factor VIII (FVIII) inhibitor testing on a series of samples over a 13-year period. Samples from seven different subjects were distributed for analysis comprising the following: four different subjects with severe hemophilia A with antibodies following replacement therapy, one subject with acquired hemophilia A and antibodies to FVIII, one subject with normal FVIII and an easily detected lupus anticoagulant, and one subject with mild hemophilia A and a difficult-to-detect lupus anticoagulant but without antibodies to FVIII. In all of the surveys the results obtained in different centers analyzing the same sample varied to an extent that would influence patient management decisions.

Quality assessment in point-of-care coagulation testing.

Point-of-care (POC) testing in the field of hemostasis is rapidly expanding in many countries. This includes use of global tests of hemostasis in operating theaters and especially use of POC monitors for determination of the international normalized ratio (INR) for monitoring oral anticoagulant therapy. Issues related to internal quality control and external quality assessment for these devices are reviewed.

Laboratory D-dimer measurement: improved agreement between methods through calibration.

Accurate and precise measurement of plasma D-dimer levels is important in the diagnosis and management of venous thromboembolism. Considerable variability in D-dimer results obtained using different methods has, however, been reported in multicentre studies. This study explored in two separate multicentre exercises the degree of precision amongst laboratory D-dimer measurements, and the degree by which inter-method agreement could be improved using a calibration curve model.

Multicentre ISI assignment and calibration of the INR measuring range of a new point-of-care system designed for home monitoring of oral anticoagulation therapy.

The new CoaguChek XS system is designed for use in patient selftesting. It is the successor of the current CoaguChek S system. The detection principle is based on the amperometric measurement of the thrombin activity initiated by starting the coagulation cascade using a human recombinant thromboplastin.

Emerging technologies and quality assurance: the United Kingdom National External Quality Assessment Scheme perspective.

The pattern of tests employed and technologies developed within hemostasis laboratories has changed considerably within the last 10 years. These changes have presented challenges to external quality assessment (EQA) providers, including the United Kingdom National External Quality Assessment Scheme (NEQAS). EQA for point-of-care devices used for monitoring oral anticoagulant therapy has focused on provision of suitable material to assess performance of devices designed for capillary blood testing, and on education of a user group not usually trained in laboratory quality control procedures.

Point-of-care International Normalised Ratios: UK NEQAS experience demonstrates necessity for proficiency testing of three different monitors.

External quality assessment (EQA) or proficiency testing is widely considered to be necessary for International Normalised Ratio (INR) determinations performed in conventional laboratory settings. There is increasing use of near-patient-test (NPT) or point-of-care (POC) INR devices and it is not known whether EQA is also necessary for these monitors. We report here on six years experience of proficiency testing for POC monitors used by health care professionals.