A retrospective analysis of discordances between international normalized ratio (INR) self-testing and INR laboratory testing in a pediatric patient population.

INTRODUCTION: The lack of quality control procedures for home point-of-care (POC) international normalized ratio (INR) devices is a concern. Concomitant laboratory and POC INR testing may be proposed to overcome the lack of quality control. However, a difference between the POC INR and the laboratory INR is not necessarily due to failure of the POC device. This study aimed to identify variables associated with a significant deviation between the POC INR and the laboratory INR. METHODS: Children included in this retrospective cohort study performed at least one concomitant laboratory and POC INRs. Clinical and laboratory variables were assessed for an association with significant deviation within pairs of INR. RESULTS: A significant deviation was noted for 30 (15.3%) of the 196 pairs of INR measurements from 124 children. Relative to patients without deviations, patients with deviations were younger (odds ratio =0.91; P = .020), less experienced in the use of POC INR devices (odds ratio =0.89; P = .098), and more likely to have received an INR result from a laboratory using animal thromboplastin (odds ratio =2.81 vs. 0.37 for laboratories using human thromboplastin; P = .016). In a multivariate analysis, younger age and the laboratory's use of animal thromboplastin were associated with significant deviations. CONCLUSIONS: Although most children had coherent pairs of INR values, the occurrence of deviations raises the question of the origin of the thromboplastin used in the laboratory and emphasizes the need to provide specific quality control procedures for POC INR devices.

Standardization of Prothrombin Time/International Normalized Ratio (PT/INR).

The prothrombin time (PT) represents the most commonly used coagulation test in clinical laboratories. The PT is mathematically converted to the international normalized ratio (INR) for use in monitoring anticoagulant therapy with vitamin K antagonists such as warfarin in order to provide test results that are adjusted for thromboplastin and instrument used. The INR is created using two major PT 'correction factors', namely the mean normal PT (MNPT) and the international sensitivity index (ISI). Manufacturers of reagents and coagulometers have made some efforts to harmonizing INRs, for example, by tailoring reagents to specific coagulometers and provide associated ISI values. Thus, two types of ISIs may be generated, with one being a 'general' or 'generic' ISI and others being reagent/coagulometer-specific ISI values. Although these play a crucial role in improving INR results between laboratories, these laboratories reported INR values are known to still differ, even when laboratories use the same thromboplastin reagent and coagulometer. Moreover, ISI values for a specific thromboplastin can vary among different models of coagulometers from a manufacturer using the same method for clot identification. All these factors can be sources of error for INR reporting, which in turn can significantly affect patient management. In this narrative review, we provide some guidance to appropriate ISI verification/validation, which may help decrease the variability in cross laboratory reporting of INRs.

[GFHT proposals for management of discordance between the International normalized ratio measured in the laboratory and by self-testing]. / Propositions du GFHT pour la gestion des discordances entre l'International normalized ratio mesuré au laboratoire et en automesure.

The lack of quality control for patient point-of-care (POC) INR devices is an issue that has led the French health authorities to make recommendations: a laboratory INR (lab INR) has to be performed at the same time as the POC INR every 6 months. However, the differences observed between the two INRs, POC and lab INRs, are not necessarily due to a failure of the POC INR device. We present here a review of the different causes of discrepancies between INR results, which are the basis of the proposals of the Groupe français d'études sur l'hémostase et la thrombose (GFHT) on the management of lab and POC INR discrepancies. Pre-analytical conditions may account for discrepancies (sampling, transport and storage conditions), as well as analytical factors (mainly the nature of the thromboplastin used) and the clinical context (inflammatory or autoimmune diseases, polycythaemia...). The interpretation of INR discrepancies is not always easy and these proposals aim at standardizing the procedure to be followed in order to make the most appropriate decision for the patient.

Assignment of international normalized ratio to frozen and freeze-dried pooled plasmas.

Objectives Frozen and freeze-dried plasmas may be used for local prothrombin time system calibration, for direct international normalized ratio (INR) determination, and for quality assessment. The purpose of the present study was to evaluate the usefulness of INRs assigned with various types of thromboplastins to frozen and freeze-dried pooled plasmas obtained from patients treated with vitamin K antagonists. Methods INRs were calculated according to the international sensitivity index (ISI) model using various thromboplastins and instruments, i.e. International Standards for thromboplastin as well as six commercial reagents prepared from rabbit and bovine brain, and recombinant human tissue factor. The uncertainty of the INRs was assessed using the standard deviations of clotting times and ISI values. Commutability of the plasmas was assessed according to the approved Clinical and Laboratory Standards Institute (CLSI) Guideline EP30-A. Validation of a set of six frozen plasma pools for direct INR determination was performed according to the Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis (SSC/ISTH) guidelines. Results For all frozen and freeze-dried plasmas, the INRs calculated with bovine thromboplastin Thrombotest were lower than the INRs assigned with other thromboplastins. With a few exceptions, the frozen and freeze-dried pooled plasmas were commutable. When the set of six frozen plasma pools was used for local calibration, the analytical bias of the INR was less than ±10% for all commercial reagents except Thrombotest. Conclusions Processing of fresh plasmas to prepare pooled frozen plasmas and freeze-dried plasmas may lead to different INR assignments depending on the thromboplastin used. Despite minor INR differences, a set of six frozen plasma pools could be used for local calibration by direct INR determination.

From Hemophilia to Deep Venous Thrombosis Patient Samples: How to Perform an Easy Coagulometer Validation Process According to Available Guidelines.

Validation protocols for the evaluation of coagulometers are needed to help professionals select the most suitable system for their regular laboratory routines. The objective of this study was to show how high standard protocols for the coagulometer validation process can fit into the daily laboratory routine. For this study, 45 healthy individuals and 112 patient samples were analyzed. From the patient samples, 51 were investigated for deep venous thrombosis, 27 for coagulopathy, 19 for antivitamin K therapy, and 15 for hemophilia. For the assessment, the performance of the 3 coagulometers and 1 point-of-care device was considered. One of the coagulometers was a new acquisition evaluated for precision, linearity, throughput, and carryover in the first moment, and the new coagulometer was then compared with the other well-established equipment in the laboratory. In normal plasma, coefficient of variation was ≤1.8% for total precision in screening tests and ≤3.5% for within-run precision in specific assays. For prothrombin time/international normalized ratio, no significant difference was found when comparing methods. Our study showed how to compare the capacity of a reagent in order to discriminate patients with severe hemophilia from patients with moderated hemophilia, and the κ coefficient agreement was 0.669 (95% confidence interval: 0.3-1.0; P < .001). d-dimer evaluated in patients with deep venous thrombosis and controls showed a 20% discrepancy between the methods. In our experience across Latin America, the number of laboratories that has performed this process is limited. In this study, we demonstrated how to adapt the validation process for the hemostasis laboratory routine to help the professional chose the best and more suitable option.

Evaluation of a new thromboplastin reagent STA-NeoPTimal on a STA R Max analyzer for the measurement of prothrombin time, international normalized ratio and extrinsic factor levels.

INTRODUCTION: We aimed at evaluating the performance of a new prothrombin time (PT) reagent (STA-NeoPTimal) with two other PT reagents (STA-Neoplastine R and STA-Neoplastine CI Plus) and the reference PT reagent used in our laboratory (ReadiPlasTin). METHODS: Evaluation consisted in intra- and interassay precision assessment, determination of sensitivity to unfractionated heparin (UFH) or enoxaparin in spiked samples and to direct oral anticoagulants (DOACs) in patients (n = 43). Method comparison of the 4 PT reagents, factor II, V, VII and X assays was tested on normal (n = 20) and abnormal samples: VKA (n = 47), preoperative (n = 23), liver failure (n = 12) and burned patients (n = 37). RESULTS: Analytical performance met manufacturers' criteria for all reagents. All PT reagents gave correlation coefficients >0.8 and even >0.9 in many situations. In some VKA samples, differences ≥ 0.5 INR units were found in samples within and above therapeutic ranges. For burned patients, PT correlations were good but with some minimal bias (<5.0%) while factor assays gave very consistent results (R > .8 and mainly >0.9). As expected, poor responsiveness of the PT to DOAC concentrations was observed with all four assays. CONCLUSION: The STA-NeoPTimal showed comparable performance to ReadiPlasTin, making it suitable for VKA control, detection of factors II, V, VII, X deficiency and assessment of liver disease coagulopathy. However, for patients receiving VKA, some significant differences were observed. We confirmed the inability of the PT assay to detect residual DOAC concentrations. Finally, burned patients results showed that recombinant thromboplastins were less sensitive to factor deficiencies in comparison to extraction thromboplastins.

Emergency medicine misconceptions: Utility of routine coagulation panels in the emergency department setting.

BACKGROUND: Coagulation panels are ordered for a variety of conditions in the emergency department (ED). OBJECTIVE: This narrative review evaluates specific conditions for which a coagulation panel is commonly ordered but has limited utility in medical decision-making. DISCUSSION: Coagulation panels consist of partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR). These tests evaluate the coagulation pathway which leads to formation of a fibrin clot. The coagulation panel can monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, evaluate for malnutrition or severe systemic disease, and assess hemostatic function in the setting of bleeding. The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels. Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding. Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function. CONCLUSIONS: Little utility for coagulation assessment is present for the evaluation of chest pain, routine perioperative assessment, initiation of anticoagulation, and screening for admitted patients. However, coagulation panel assessment should be considered in patients with hemorrhage, patients on anticoagulation, and personal history or family history of bleeding.

Does telehealth improve anticoagulation management in patient service centers (PSC)? A pilot project.

Anticoagulation Management Services (AMS) are known to improve warfarin management in the outpatient setting. The guideline recommendations are well established and indicate that patients who receive a Vitamin K antagonist (VKA) should be under the care of an experienced and specialized anticoagulation clinic (Lip et al. in Chest 154(5):1121-1201, 2018). Warfarin, a VKA, is considered a high risk medication and one of the most common causes of adverse events with poor patient outcomes. Anticoagulation care is assessed by measuring the percent of Time in Therapeutic Range (TTR) in patients receiving a VKA. Evidence shows that a 10% improvement in TTR has been associated with a 10% reduction in adverse event rates. Optimal management over usual medical care should prevent 7 myocardial infarctions, strokes, major bleeds, or deaths per 100 patients/year (Bussey et al. in Pharmacotherapy 9(4):214-219, 1989). Telehealth or telemedicine can be defined as the use of electronic information along with telecommunication technologies to provide medical services to individuals that are in remote locations from each other (Perednia in JAMA 273(6):483-488, 1995; Gray et al in J Thromb Thrombolysis 2019(48):690-693, 2019). This technology allows a provider located at a distant site to use two-way audio visual electronic communication to deliver clinical health care services to a patient who is located at an originating site (Kristian et al. Int J Technol Assess Health Care 28(1):44-51, 2012; Testa and Zimmermann in Telemedicine for managing patients on oral anticoagulant, 2011; Telehealth Services in CMS Manual System Pub 100-04 medicare claims processing, 2019). The goals of the Telehealth Anticoagulation Management Service are to: (1) increase patient satisfaction (2) reduce turnaround time for results by providing the INR (International Normal Ratio) results in real time (3) increase patient compliance to INR testing and (4) improve system wide anticoagulation care by increasing cTTR (center Time in Therapeutic Range) metrics to high quality metrics of 65% and above. The overarching goal of our health system Telehealth program was to develop a collaborative care telemedicine INR model in collaboration with core laboratories (Patient Service Centers or PSCs) in order to improve patient quality metrics on warfarin. In this model, the Tele-ACTS Center (Telehealth Anticoagulation and Clinical Thrombosis Service) team was able to provide distant care for the outpatient population on warfarin maintenance therapy using a virtual telemedicine INR model located in a distant location to the PSC. Using this model, we were able to improve center-based TTR by 45.73%.

Determination of the cut-off prothrombin time to estimate plasma rivaroxaban overdose status.

Laboratory monitoring of rivaroxaban (RIV) is required under certain conditions. Mass spectrometry and anti-factor Xa assays are the recommended methods, which may not be readily available. Prothrombin time (PT) is the most widely used and simple coagulation assay. To set the cutoff PT and international normalized ratio (INR) to estimate RIV overdose status. RIV-spiked pooled normal plasma was used. PT test was performed using a CA-7000 coagulometer and Thromborel S reagent. The precise measurement of RIV concentration at the cut-off PT was evaluated according to the Clinical and Laboratory Standard Institute (CLSI) EP12-A2 guideline. The RIV concentration at 275 ng/mL was analyzed using 40 replicates. Receiver operating characteristic (ROC) analysis was performed to determine the cutoff value for the determination of RIV potential overdose status. An imprecision estimation of PT was conducted with 220.00 ng/mL, 247.50 ng/mL, 261.25 ng/mL, 288.75 ng/mL, 302.50 ng/mL and 330.00 ng/mL concentrations of RIV in 60 replicates. According to the ROC analysis, the cutoff clotting times and INR values to determine the overdose status of RIV were 13.45 s and 1.39. With these values, there was a 92.6% probability that plasma samples with RIV concentration ≤ 247.50 ng/mL yielded consistently negative (on-therapy dose) results, and those with ≥ 302.50 ng/mL yield consistent positive (potential overdose) results using our PT assay. PT with a reliable cutoff clotting time and INR can be used to determine the potential overdose status of RIV to facilitate the diagnosis and treatment by controlling the dose.

The Cost of Pre-Analytical Errors in INR Testing at a Tertiary-Care Hospital Laboratory: Potential for Significant Cost Savings.

BACKGROUND: Preanalytical errors account for most laboratory errors. Although the frequencies of preanalytical errors are well characterized in the literature, little is known regarding the costs of these errors to the laboratory. OBJECTIVE: To analyze costs associated with preanalytical errors associated with the international normalized ratio (INR) test. METHODS: We performed a retrospective analysis of INR requests associated with preanalytical error codes from January 2009 through September 2013. Preanalytical error types were those related to order entry (no specimen collected) and those unrelated to order entry (insufficient specimen quantity or specimen-integrity concerns). We calculated the cost of analysis of a specimen and the cost of investigating errors. RESULTS: During the study period, there were 557,411 INR requests, 13.1% of which were associated with a preanalytical error code. The total annual cost of INR testing was USD $379,222.50. Investigation and reporting of preanalytical errors not related to order entry represented 10.5% of our annual INR testing budget (USD $39,939.00). CONCLUSIONS: Minimizing preanalytical errors has the potential to result in significant cost savings.

Assessment of agreement and time in therapeutic range of capillary versus venous international normalised ratio in frail elderly people in a nursing home.

Vitamin K antagonists are widely used, yet have a slim therapeutic margin and high iatrogenicity. Patients are monitored through international normalised ratio (INR) by venipuncture, but coagulometers could measure INR by capillary puncture. This prospective study evaluated the clinical concordance of capillary INR versus venous INR in 31 nursing home patients. Concordance was good and mean time in therapeutic range (TTR) markedly increased. Capillary INR is thus reliable, could improve TTR and decrease iatrogenicity.

Estudio comparativo de equipos INR capilar "point of care" versus INR venoso, en pacientes en tratamiento con antagonistas de vitamina K / Comparison of point of care capillary international normalized ratio (INR) with INR measured in venous samples

Background: INR is used to monitor the treatment with vitamin K antagonists. A strategy to reduce waiting times for sampling is to measure INR in a capillary sample using a portable point of care (POC) type coagulometer. Aim: To evaluate the correlation of CoaguChek Pro II™, Xprecia™ and microINR™ with venous INR measured at the clinical laboratory and their ease of use. Materials and Methods: Patients provided capillary and venous blood samples for parallel tests comparing Xprecia™ Stride with CoaguChek Pro II™ and with venous INR, microINR™ with CoaguChek Pro IITM and with venous INR. The devices' ease of use was assessed surveying the sampling staff. Results: The three tested devices had good correlation coefficients with venous INR: CoaguChek Pro IITM 0.953 and 0.962; Xprecia™ of 0.912 and microINR™ of 0.932. The correlation coefficient of Xprecia™ with CoaguChek Pro IITM was 0.937 and microINR™ with CoaguChek Pro IITM was 0.976. Conclusions: CoaguChek Pro IITM, Xprecia™ and microINR™ results had a good correlation coefficient with INR measured at the laboratory. Our results indicate that, in the hands of trained users, POC-type coagulometers are reliable and acceptable for routine use in anticoagulant treatment control.

Analysis of Factors That Interrupt With INR Control in the First Anticoagulation Clinic Monitoring Jordanian Patients.

Multiple factors such as vitamin K consumption, drug interactions, herbs interactions, disease states, and alcohol intake affect international normalized ratio (INR) values and thus warfarin dosing. These variables have been described in general and for all patients in the literature. In contrast, the factors that affect INR control in a specific population are rarely studied. Being aware of these factors contributes a lot in maintaining an INR control and avoiding the supratherapeutic or subtherapeutic anticoagulation and the associated risks of hemorrhage or thromboembolism. The aim of this study is to recognize the specific population factors in Jordanian patients that interrupt INR control. Such recognition provides clinical pharmacists managing the anti-coagulation clinic (ACC) with necessary tools and predictors of dose adjustment, nontarget INR handling, and points to add on to the educational session. A total of 2788 patients were referred to the first clinical pharmacists managed ACC at Queen Alia Heart Institute-the only official referral hospital for cardiac patients in Jordan-for education and monitoring between November 1, 2013, and November 1, 2016. We evaluated specific population factors that interrupt INR control using a pretested, structured clinical data collection form. The patients were followed up regularly for achieving target INR (TINR). For patients who were not achieving TINR, the possible cause was examined thoroughly by reviewing the patient's medical file for recent medication intake, comorbidities, and laboratory results. Then the patients or their caregiver were asked direct questions regarding their diet, food supplements, cigarette smoking, shisha smoking, alcohol intake, herbs, and complementary medicine use and compliance, in addition to performing pharmacogenetic testing (polymorphisms of vitamin K-epoxide reductase complex [VKORC1] and cytochrome P450 2C9 [CYP2C9] genes) in special cases. For a total of 2788 patients, 89 488 INR values were included in the study. Of all, 20 365 (22.8%) were non-TINR values, 13 145 (14%) were subtherapeutic, and 7220 (8.1%) were supratherapeutic. All patients included in the study had a non-TINR at least 3 times (n = 65, 2.3%) and as frequent as 50 times (n = 21, 0.8%) during the study period. Non-TINR values ranged from 1 to 11. Serious side effects reported in 7 patients with uncontrolled INR, 6 were bleeding, which required hospitalization (2 upper gastrointestinal [GI] bleeding, 3 nasal bleeding, and 1 eye bleeding), 1 was cerebrovascular accident (CVA thrombolytic). Factors that interrupted INR control in our population, arranged in descending sequence, were concurrent medication use 46.9% (mainly Salicylates and Amiodarone), smoking cigarettes and shisha 17% (represented the most frequent single factor that caused non-TINR in the present study), a nonbalanced dietary vitamin K intake 16.88% caused changes in INR (lower) was related to an increase in the intake of vitamin K-rich food, were noticed to be much more in the spring season in Jordan (end of March and April mainly), herbal supplements 15.02%; Hawthorn (Crataegus, الزعرور) is an herb that lives widely in Jordan, and shockingly we found that it is used very commonly in our ACC patients and corresponded to an elevated INR <8 in 11 patients, and serious bleeding events that required hospitalization in 2 cases), noncompliance 1.49%, comorbid diseases 1%, malabsorption 0.53%, alcohol intake 0.39%, and VKORC1 A/G and CYP2C9 *1*1 genotype 0.15%. The analysis of factors that interrupted with INR control in our patients were both predicted and distinctive; most of these factors were reported previously by other researchers. On the other hand, many of the previously reported factors were not frequently detected in our patients, and the frequency of each of the realized factors was contributed differently to non-TINR in our population. Alarming factors causing non-TINR detected in our study include smoking both cigarettes and shisha, herbal use (Hawthorn and Ginseng), increased intake of vitamin K rich food in the spring season, and concurrent medication use (Salicylates, Amiodarone, Ciprofloxacin, nonsteroidal anti-inflammatory drugs [NSAIDS], Azithromycin, Clarithromycin: although the use of these drugs is mandatory sometimes, it can be replaced by an alternative, eg, antibiotics or monitored closely together with warfarin).

International normalized ratio control and subsequent clinical outcomes in patients with atrial fibrillation using warfarin.

We explored associations between INR measures and clinical outcomes in patients with AF using warfarin, and whether INR history predicted future INR measurements. We included patients in ARISTOTLE who were randomized to and received warfarin. Among patients who had events, we included those with ≥ 3 INR values in the 180 days prior to the event, with the most recent ≤ 60 days prior to the event, who were on warfarin at the time of event (n = 545). Non-event patients were included in the control group if they had ≥ 180 days of warfarin exposure with ≥ 3 INR measurements (n = 7259). The median (25th, 75th) number of INR values per patient was 29 (21, 38) over a median follow-up of 1.8 years. A total of 87% had at least one INR value < 1.5; 49% had at least one value > 4.0. The last INRs before events (median 14 [24, 7] days) were < 3.0 for at least 75% of patients with major bleeding and > 2.0 for half of patients with ischemic stroke. Historic time in therapeutic range (TTR) was weakly associated with future TTR (R2 = 0.212). Historic TTR ≥ 80% had limited predictive ability to discriminate future TTR ≥ 80% (C index 0.61). In patients with AF receiving warfarin, most bleeding events may not have been preventable despite careful INR control. Our findings suggest that INRs collected through routine management are not sufficiently predictive to provide reassurance about future time in therapeutic range or to prevent subsequent outcomes, and might be over-interpreted in clinical practice.

Pharmacist-led medicine use review in community pharmacy for patients on warfarin.

Background Medicine use review by pharmacists has the potential to improve anticoagulation therapy management in patients on warfarin. Objective To develop, implement and evaluate a pharmacist-led medication use review service for patients on warfarin. Setting Six community pharmacies in Malta. Method Patients (N = 100) aged 18 or older and on warfarin were recruited through pre-selected community-pharmacies. These patients were then invited to attend two sessions: a review session (t1) and a follow-up session after 2 months (t2). During the medication use review session, medication reconciliation was performed (a) to detect drug-related problems using the DOCUMENT classification system, (b) to develop an individualised care plan for each patient and (c) to recommend an action for each identified problem for physician, pharmacist or patient consideration. At t2, the degree of acceptance of the recommendations was determined by assessing the number of drug-related problems for which action was taken to address the problem. International normalisation ration (INR) control was evaluated by calculating the percentage Time in Therapeutic Range (TTR) at t1 and t2 using the Rosendaal linear interpolation method. Main outcome measures Frequency and type of drug-related problems detected; percentage of accepted recommendations; and INR control. Results A total of 481 drug-related problems were identified; 40% (n = 190) were related to warfarin treatment. Need for monitoring (30%; n = 145), lack of compliance (20%; n = 97) and need for patient education (19%; n = 90) were the top three problems identified. There was a significant correlation between frequency of the problems and number of chronic medications (Spearman Correlation 0.583, p < 0.001), number of comorbidities (Spearman Correlation 0.327, p = 0.001) and older age (Spearman Correlation 0.285, p = 0.04). A total of 475 recommendations were followed-up; 49% (n = 234) were referred for consideration by the physician. The percentage of recommendations accepted (84%; n = 397) was significantly higher than the percentage of recommendations not accepted (16%; n = 78) (p < 0.001). The time in therapeutic range improved significantly from 68.7% at t1 to 79.8% at t2 (p = 0.01). Conclusions The high percentage of accepted recommendations and the improvement in INR control indicate that a pharmacist-led medication use review service in community pharmacy contributes to improving anticoagulation therapy management in patients on warfarin.

Assessment of Condition and Medication Knowledge Gaps Among Atrial Fibrillation Patients: A Systematic Review and Meta-analysis.

Background: Patient education facilitates construction of a correct illness representation, improves beliefs about medications, and improves knowledge, factors that have been associated with better adherence. Objective: Our objective was to characterize the published literature about atrial fibrillation (AF) patients' disease and medication knowledge to identify knowledge gaps and misconceptions to inform AF patient education strategies. Methods: Following PRISMA guidelines, we searched PubMed, EMBASE, CINAHL, and PsychINFO from inception to May 2018 for studies that assessed AF patients' knowledge about their condition and medications. For quantitative studies, we extracted the proportion of participants who provided correct answers to the questions asked about their condition, medications, or risk of stroke. We classified data for related questions into knowledge domains. A random-effects meta-analysis was conducted for each knowledge domain. A domain was considered a knowledge gap if the pooled mean proportion of participants who demonstrated knowledge of it was ≤50%, regardless of CI. Qualitative data were summarized narratively. Results: A total of 21 studies were included. AF- and stroke-related knowledge gaps and misconceptions included the following: AF can be asymptomatic, AF can predispose to heart failure, women are at a higher risk of stroke, the definition of ischemic stroke, and patients' awareness of their diagnosis. Medication-related knowledge gaps were antithrombotic-drug interactions, antithrombotic-food interactions, vitamin K content of foods, the term INR (international normalized ratio) and its interpretation, and the required actions in case of a missed dose. Conclusion and Relevance: This systematic review identified several AF patient knowledge gaps about their condition and its treatment that can inform the development of AF patient education programs.

Accuracy assessment of consecutive test strip lots for whole blood INR point-of-care instruments: clarifying the role of frozen plasma pools.

Background In the Netherlands, each new lot of test strips for the CoaguChek XS is validated by a group of collaborating centers. The purpose of this study was to assess the accuracy of the international normalized ratio (INR) measured with consecutive test strip lots and the suitability of frozen plasma pools for accuracy evaluation. Methods Each year, a particular lot of CoaguChek XS test strips is used as reference lot. The reference lots have been validated with the International Standard for thromboplastin rTF/09, yielding a mathematical relationship (R1) between reference lot INR and International Standard INR. New lots are compared to the reference lot using patients' capillary blood samples, yielding a relationship (R2) between the new lot INR and the reference lot INR. INRs of the blood samples were within the 1.5-4.5 interval. In parallel, three frozen plasmas pools are analyzed with the test strips. The distance of each plasma point to the line of relationship R2 was assessed. Results Fifty-four test strip lots have been evaluated during 3 years (2014-2016). Mean INR differences between test strip lot and International Standard rTF/09 varied between -0.14 and +0.20 (-4% and +8%, respectively). A positive trend with strip lot sequence number was observed (p<0.001). In several cases, the distance of the frozen plasmas to the whole blood relationship (R2) was greater than the critical value for commutability. Conclusions Using whole blood, all evaluated test strip lots met the analytical bias criterion of ±10%. Frozen plasma pools behave differently compared to whole blood and are not suitable for assessing absolute accuracy of new CoaguChek XS test strips.

[Comparison of point of care capillary international normalized ratio (INR) with INR measured in venous samples]. / Estudio comparativo de equipos INR capilar "point of care" versus INR venoso, en pacientes en tratamiento con antagonistas de vitamina K.

BACKGROUND: INR is used to monitor the treatment with vitamin K antagonists. A strategy to reduce waiting times for sampling is to measure INR in a capillary sample using a portable point of care (POC) type coagulometer. AIM: To evaluate the correlation of CoaguChek Pro II™, Xprecia™ and microINR™ with venous INR measured at the clinical laboratory and their ease of use. MATERIALS AND METHODS: Patients provided capillary and venous blood samples for parallel tests comparing Xprecia™ Stride with CoaguChek Pro II™ and with venous INR, microINR™ with CoaguChek Pro IITM and with venous INR. The devices' ease of use was assessed surveying the sampling staff. RESULTS: The three tested devices had good correlation coefficients with venous INR: CoaguChek Pro IITM 0.953 and 0.962; Xprecia™ of 0.912 and microINR™ of 0.932. The correlation coefficient of Xprecia™ with CoaguChek Pro IITM was 0.937 and microINR™ with CoaguChek Pro IITM was 0.976. CONCLUSIONS: CoaguChek Pro IITM, Xprecia™ and microINR™ results had a good correlation coefficient with INR measured at the laboratory. Our results indicate that, in the hands of trained users, POC-type coagulometers are reliable and acceptable for routine use in anticoagulant treatment control.