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Our objective was to maintain low interlaboratory variation and bias in international normalized ratio (INR) results following a network change in instrumentation and reagents, using a process of ongoing standardization and harmonization. Network-wide standardization to new common instrument and reagent platforms followed by network-wide application of a simple novel process of verification of international sensitive index and mean normal prothrombin time values for each new lot of prothrombin time (PT) reagent that does not require use of World Health Organization reference thromboplastin or INR calibration/certified plasma. The network transitioned from mechanical hemostasis detection instruments with associated PT reagent (Diagnostica Stago; NeoPTimal) to optical detection (ACL TOPs) with associated PT reagent (Werfen; RecombiPlasTin 2G). Comparing 3 years of data for each situation, the network (n = 27 laboratories) maintained low INR variability and bias relative to general mechanical and optical groups and other laboratories. Harmonized support for patient management of vitamin K antagonists such as warfarin was continuously maintained in our geography, with potentially positive implications for other coagulation laboratories and geographies. For the United States in particular, paucity of US Food and Drug Administration-cleared INR certified plasmas potentially compromises INR test accuracy; our novel approach may provide workable alternatives for other laboratories/networks.

Frequent prothrombin time (PT) and international normalized ratio (INR) testing is critical for millions of people on lifelong anticoagulation with warfarin. Currently, testing is performed in hospital laboratories or with expensive point-of-care devices limiting the ability to test frequently and affordably. We report a proof-of-concept PT/INR testing system that uses the vibration motor and camera on smartphones to track micro-mechanical movements of a copper particle. The smartphone system computed the PT/INR with inter-class correlation coefficients of 0.963 and 0.966, compared to a clinical-grade coagulation analyzer for 140 plasma samples and demonstrated similar results for 80 whole blood samples using a single drop of blood (10 μl). When tested with 79 blood samples with coagulopathic conditions, the smartphone system demonstrated a correlation of 0.974 for both PT/INR. Given the ubiquity of smartphones in the global setting, this proof-of-concept technology may provide affordable and effective PT and INR testing in low-resource environments. Therapy with anticoagulants requires frequent monitoring. Here the authors describe a proof-of-concept study of a simple and affordable blood clot test that uses a smartphone’s vibration motor and camera to track micro-movements in a single drop of blood.

The prothrombin time (PT) and activated partial thromboplastin time (APTT) are screening tests used to detect congenital or acquired bleeding disorders. An unexpected PT and/or APTT prolongation is often evaluated using a mixing test with normal plasma. Failure to correct (\"noncorrection\") prolongation upon mixing is attributed to an inhibitor, whereas \"correction\" points to factor deficiency(ies). To define an optimal method for determining correction or noncorrection of plasma mixing tests through an international, multisite study that used multiple PT and APTT reagents and well-characterized plasma samples. Each testing site was provided 22 abnormal and 25 normal donor plasma samples, and mixing studies were performed using local PT and APTT reagents. Mixing study results were evaluated using 11 different calculation methods to assess the optimal method based on the expected interpretation for factor deficiencies (correction) and noncorrection (inhibitor effect). Misprediction, which represents the failure of a mixing study interpretation method, was assessed. Percentage correction was the most suitable calculation method for interpreting PT mixing test results for nearly all reagents evaluated. Incubated PT mixing tests should not be performed. For APTT mixing tests, percentage correction should be performed, and if the result indicates a factor deficiency, this should be confirmed with the subtraction III calculation where the normal pooled plasma result (run concurrently) is subtracted from the mixing test result with correction indicated by a result of 0 or less. In general, other calculation methods evaluated that performed well in the identification of factor deficiency tended to have high misprediction rates for inhibitors and vice versa. No single method of mixing test result calculation was consistently successful in accurately distinguishing factor deficiencies from inhibitors, with between-reagent and between-site variability also identified.

Abnormal blood coagulation often occurs in critically ill patients, which seriously affects their prognosis. This retrospective study investigated the implications of changes in blood coagulation in patients with coronavirus disease 2019 (COVID-19). Records were reviewed for patients admitted with COVID-19 between February 4 and 16, 2020. The primary outcome was in-hospital death. A total of 85 patients were included, of whom 12 died in the hospital. The admission prothrombin time (PT), international normalized ratio (INR), and levels of D-dimer and fibrin/fibrinogen degradation products (FDP) were significantly higher in non-survivors than in survivors, while the reverse was true for prothrombin time activity (PT-act) and PaO2/FiO2. Multivariate logistic regression showed that PT-act < 75% was independently associated with mortality. The area under the receiver operating characteristic curves for PT-act, D-dimer, and FDP at admission could significantly predict mortality. The AUCs for PT-act were larger than those for D-dimer and FDP; however, there was no significant difference. After 2 weeks of treatment, the coagulation parameters of the surviving patients improved. COVID-19 is often accompanied by abnormal coagulation. PT-act at admission is able to predict mortality in patients with COVID-19 as can D-dimer and FDP levels. PT-act < 75% is independently associated with mortality.

Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.

Background Measurement of rivaroxaban efficacy using the rivaroxaban‐specific anti‐Xa assay (raXa) can be used for monitoring in veterinary medicine. Detection of rivaroxaban efficacy using other hemostatic tests would make monitoring timelier and more accessible. Objectives Compare results of raXa with prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, tissue factor (TF) and kaolin‐activated thromboelastography (TEG), and thrombin generation (TG) in hypercoagulable dogs. Animals Twelve client‐owned dogs, diagnosed with hypercoagulability or thromboembolic disease, and prescribed rivaroxaban, were recruited from a tertiary referral hospital from 2020 to 2022. Methods Prospective clinical trial. Jugular vein blood samples were collected before treatment, and 1 week and 1–3 months after initiation of rivaroxaban therapy. Hemostatic tests were performed at each visit (3 h after rivaroxaban dosing). TG curve parameters lag time, endogenous thrombin potential (ETP), peak, and time to peak (ttpeak) were assessed. Results There was a significant linear relationship between raXa and PT (r2 = 0.74, p < 0.001), ETP (r2 = 0.83, p < 0.001), lag time (r2 = 0.87, p < 0.001), peak (r2 = 0.86, p < 0.001), and ttpeak (r2 = 0.86, p < 0.001). There was a weak linear relationship between raXa and kaolin‐activated TEG parameter reaction time (R) (r2 = 0.49, p = 0.026). There was no significant relationship between raXa and aPTT, fibrinogen concentration and the remainder of the TEG variables (p > 0.05). Conclusion and Clinical Importance PT and TG correlated with raXa. PT performed at a reference laboratory appeared to be a convenient method to monitor a small cohort of dogs receiving rivaroxaban therapy.

The processes of blood coagulation and fibrinolysis that in part maintain the physical integrity of the circulatory system and fluidity of its contents are complex as they are critical for life. While the roles played by cellular components and circulating proteins in coagulation and fibrinolysis are widely acknowledged, the impact of metals on these processes is at best underappreciated. In this narrative review we identify twenty-five metals that can modulate the activity of platelets, plasmatic coagulation, and fibrinolysis as determined by in vitro and in vivo investigations involving several species besides human beings. When possible, the molecular interactions of the various metals with key cells and proteins of the hemostatic system were identified and displayed in detail. It is our intention that this work serve not as an ending point, but rather as a fair evaluation of what mechanisms concerning metal interactions with the hemostatic system have been elucidated, and as a beacon to guide future investigation.

Alginate-based materials have gained significant recognition in the medical industry due to their favorable biochemical properties. As a continuation of our previous studies, we have introduced a new composite consisting of cellulose nonwoven fabric charged with a metallic copper core (CNW-Cu0) covered with a calcium alginate (ALG−Ca2+) layer. The preparation process for these materials involved three main steps: coating the cellulose nonwoven fabric with copper via magnetron sputtering (CNW → CNW-Cu0), subsequent deposition with sodium alginate (CNW-Cu0 → CNW-Cu0/ALG−Na+), followed by cross-linking the alginate chains with calcium ions (CNW-Cu0/ALG−Na+ → CNW-Cu0/ALG−Ca2+). The primary objective of the work was to supply these composites with such biological attributes as antibacterial and hemostatic activity. Namely, equipping the antibacterial materials (copper action on representative Gram-positive and Gram-negative bacteria and fungal strains) with induction of blood plasma clotting processes (activated partial thromboplastin time (aPTT) and prothrombin time (PT)). We determined the effect of CNW-Cu0/ALG−Ca2+ materials on the viability of Peripheral blood mononuclear (PBM) cells. Moreover, we studied the interactions of CNW-Cu0/ALG−Ca2+ materials with DNA using the relaxation plasmid assay. However, results showed CNW-Cu0/ALG−Ca2+’s cytotoxic properties against PBM cells in a time-dependent manner. Furthermore, the CNW-Cu0/ALG−Ca2+ composite exhibited the potential to interact directly with DNA. The results demonstrated that the CNW-Cu0/ALG−Ca2+ composites synthesized show promising potential for wound dressing applications.

Injury results in more deaths in children than all other causes combined, but there is little data regarding the association of early coagulopathy on outcomes in pediatric patients with traumatic injuries. The aim of this study was to determine the optimal cut-off value for the Prothrombin Time ratio (PTr) and to show the diagnostic characteristics of the PTr to predict mortality. We retrospectively included during 4 years all patients less than 16 years old referred to our trauma center for traumatic injury with ISS ≥9. A total of 272 children were included. Mean age was 9.4 ± 4.8 years and median ISS was 17 [interquartile range, 12 to 26]. Day 28 mortality was 6.7%. The optimal cut-off value in our population for predicting day 28 mortality was 1.24. Using this value, the sensitivity of PTr was 84%, specificity was 82%, positive likelihood ratio was 4.7, and negative likelihood ratio was 0.19. Early mortality (i.e., mortality at 24 h) was also well-predicted (1.0% versus 16.4%, p < .0001), as the need for massive transfuion. Similarly, patients with PTr ≥1.24 at admission presented with a higher rate of severe thoracic and abdominal trauma, higher ISS, higher likelihood of admission to an intensive care unit, longer hospitalization, and higher rate of significant procedure (e.g., surgery or embolization). Trauma-induced coagulopathy defined only by a PTr ≥1.24 could be used as a severity predictive marker and as a sensitive, specific, quick, and easy to use tool for admission triage of pediatric patients. •Among 272 children with trauma injury, an admission PTr ≥1.24 was determined as a significant value to predict mortality.•Mortality at 24 h was well predictable using a cutoff of PTr ≥1.24 (1.0% versus 16.4%, p < .0001).•An early diagnosis of acute trauma-induced coagulopathy could be useful for admission triage of pediatric patients.

Anticoagulation (AC) is effective in reducing thromboembolic events for individuals with atrial fibrillation (AF) or mechanical heart valve (MHV), but maintaining patients in target range for international normalized ratio (INR) can be difficult. Evidence suggests increasing INR testing frequency can improve time in target range (TTR), but this can be impractical with in-clinic testing. The objective of this study was to test the hypothesis that more frequent patient-self testing (PST) via home monitoring increases TTR. This planned substudy was conducted as part of The Home INR Study, a randomized controlled trial of in-clinic INR testing every 4 weeks versus PST at three different intervals. The setting for this study was 6 VA centers across the United States. 1,029 candidates with AF or MHV were trained and tested for competency using ProTime INR meters; 787 patients were deemed competent and, after second consent, randomized across four arms: high quality AC management (HQACM) in a dedicated clinic, with venous INR testing once every 4 weeks; and telephone monitored PST once every 4 weeks; weekly; and twice weekly. The primary endpoint was TTR at 1-year follow-up. The secondary endpoints were: major bleed, stroke and death, and quality of life. Results showed that TTR increased as testing frequency increased (59.9 ± 16.7 %, 63.3 ± 14.3 %, and 66.8 ± 13.2 % [mean ± SD] for the groups that underwent PST every 4 weeks, weekly and twice weekly, respectively). The proportion of poorly managed patients (i.e., TTR <50 %) was significantly lower for groups that underwent PST versus HQACM, and the proportion decreased as testing frequency increased. Patients and their care providers were unblinded given the nature of PST and HQACM. In conclusion, more frequent PST improved TTR and reduced the proportion of poorly managed patients.