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.

Security and cost comparison of INR self-testing and conventional hospital INR testing in patients with mechanical heart valve replacement.

BACKGROUND: International normalized ratio (INR) self-testing can improve the management of anticoagulation therapy with warfarin for the patients following mechanical heart valve replacement. Several reviews and studies have demonstrated self-management as an option to improve patient's outcome considerably after mechanical heart valve replacement. We sought to analyze the security, economy and discuss the prospect of self-testing of anticoagulation therapy in patients following mechanical heart valve replacement in China, and evaluate the accuracy and stability of CoaguChek XS portable INR-testing device. METHODS: This was a prospective self-controlled clinical study conducted with 526 patients receiving oral warfarin anticoagulation therapy after mechanical heart valve replacement in the period of Mar.1, 2012 - Nov.1, 2012 in Cardiovascular Surgery Department of West China Hospital of Sichuan University. The same patient performed INR testing with CoaguChek XS portable coagulometer (group1) and central lab (group 2) in parallel. The follow-up time was 6 months. Meanwhile, a questionnaire was handed out to survey the expenses required for the re-examination visits to the hospital, time, and anticoagulation complications. RESULTS: No severe anticoagulation complications occurred in all the patients. No significant difference of the INR results were observed between group 1 and group 2, they showed significant relevance, r = 0.953(p < 0.05). Compared with the conventional method of INR testing in hospital, the portable coagulometer is convenient, quick and less traumatic. Self-testing of anticoagulation therapy reduced the cost and the time required for re-examination. CONCLUSIONS: Results of CoaguChek XS monitor are precise and have a good consistency and stability as compared with traditional laboratory testing. For the patients receiving anticoagulation therapy after mechanical heart valve replacement, the self-testing of anticoagulation therapy with portable coagulometer is a safe choice, and it has a promising future application in China.

Assessment of a portable prothrombin time analyzer (CoaguChek-XS) in dogs.

OBJECTIVES: To assess the performance of a portable prothrombin time (PT) analyzer (CoaguChek-XS) in dogs. ANIMALS: Ninety-seven dogs composed of 20 healthy dogs, 45 ill dogs, and 32 ill dogs with altered coagulation. PROCEDURES: Samples were concurrently obtained and PT was measured using the CoaguChek-XS and an automated coagulation analyzer. Agreement between methods was assessed using Spearman's correlation and Bland-Altman analysis. RESULTS: The reference interval for PT using the CoaguChek-XS was 9.6-11.5 s. The CoaguChek-XS was easy to use, required a small volume of whole blood, and gave results within 1 min. The mean difference in PT between the 2 methods was 2.58 s (SD 3.10), and 94% of the samples fell within limits of agreement. The correlation was moderate, but significant (r = 0.35, P < 0.001). Sensitivity and specificity of the CoaguCheck-XS PT compared to analyzer PT were 92% and 56%, respectively, and increased to 95% and 77% on intent to treat basis. The coefficient of variance was 0.72%. The CoaguChek-XS identified all 8 dogs with anticoagulant rodenticide intoxication, although a discrepancy was noted from the analyzer results. In anemic dogs (PCV≤25%), the CoaguChek-XS did not display accurate results. CONCLUSIONS: The CoaguChek-XS is a simple, user-friendly, highly precise PT analyzer. Results had moderate correlation and good agreement with a standard method. It can be used reliably for screening dogs when the PT is normal. However, when the CoaguChek-XS PT is prolonged or when the PCV is ≤25%, results should be confirmed using a standard method.

The international normalized ratio according to Owren in liver disease: interlaboratory assessment and determination of international sensitivity index.

INTRODUCTION: The international normalized ratio (INR) is used to prioritize liver disease patients for transplantation. Previous studies have shown high interlaboratory variability in Quick-based INR determinations in samples of patients with liver disease. We assessed Owren-based INR reagents for analyzing INR in patients with liver disease. Further, we determined the difference between international sensitivity index (ISI) for patients on vitamin K antagonists (ISIVKA) and ISI for patients with liver disease (ISIliver). PATIENTS AND METHODS: Twenty patients with liver disease were included, 10 with INR 1.8-3.6 (group A1) and 10 with INR 1.2-1.5 (group C1). Plasma from these patients was analyzed for Owren-based INR in eight Swedish laboratories using either of following reagents: SPA+, Owrens PT or Nycotest PT. To determine ISI liver, the reference thromboplastin RBT/05 and additional 41 patients with liver disease and 20 normal controls were included. ISIVKA was determined according to the WHO procedure. The difference between the ISIVKA and ISIliver was calculated. RESULTS: The coefficients of variance for the Owren based INR methods were 6.2% in group A1, 3.9 % in group C1 and 5.3% for all patients. The difference between ISIVKA and ISIliver were -0.4%, -0.7% and -0.2% for SPA+, Owrens PT and Nycotest PT respectively. CONCLUSIONS: Interlaboratory variation in INR analyses according to Owren in patients with liver disease is low and the difference between ISIVKA and ISIliver is below 10% with this method. ISIVKA can therefore be used in the INR calibration, for the Owren reagents studied, when analyzing plasma from patients with liver disease.

The economic costs of routine INR monitoring in infants and children--examining point-of-care devices used within the home setting compared to traditional anticoagulation clinic monitoring.

INTRODUCTION: The use of point-of-care (POC) devices within the home for routine INR monitoring has demonstrated reliability, safety and effectiveness in the management of infants and children requiring long-term warfarin therapy. However, a comprehensive cost-analysis of using this method of management, compared to attending anticoagulation clinics has not been reported. The aim of this study was to compare the estimated societal costs of attending anticoagulation clinics for routine INR monitoring to using a POC test in the home. MATERIALS AND METHODS: This study used a comparative before-and-after design that included 60 infants and children managed via the Haematology department at a tertiary paediatric centre. Each participant was exposed to both modes of management at various times for a period of ≥3 months. A questionnaire, consisting of 25 questions was sent to families to complete and return. Data collected included: the frequency of monitoring, mode of travel to and from clinics, total time consumed, and primary carer's income level. RESULTS: The home monitoring cohort saved a total of 1 hour 19 minutes per INR test compared to attending anticoagulation clinics and had a cost saving to society of $66.83 (AUD) per INR test compared to traditional care; incorporating health sector costs, travel expenses and lost time. CONCLUSIONS: The traditional model of care requires a considerable investment of time per test from both child and carer. Home INR monitoring in infants and children provides greater societal economic benefits compared to traditional models.

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. AIM: To assess the quality of INR results for users of two POC devices (CoaguChek XS and CoaguChek XS Plus) over a four-year period. METHODS: Four surveys (two samples) were sent in each 12-month period. The median INR value of each sample was calculated and the percentage deviation from this median determined. Any results greater than 15% from the median were considered to be outside consensus which indicated a possible problem within the testing system. RESULTS: Variability of INR results in this UK National External Quality Assessment Scheme (NEQAS) programme was comparable to that in the UK NEQAS EQA programme for laboratory INR testing. Occurrence of persistent problems was lower in the POC programme than the laboratory programme. CONCLUSIONS: Utilisation of an EQA programme for POC devices in primary care is feasible and necessary. Our data suggest for those health professionals using EQA, the reliability and accuracy of INR testing matches the quality of laboratory testing.

Feasibility, cost-effectiveness and patients' acceptance of point-of-care INR testing in a hospital-based anticoagulation clinic.

Point-of-care (POC) coagulometers are increasingly used by patients for self-monitoring of oral vitamin K antagonists therapy. We studied the feasibility of introducing POC international normalised ratio (INR) testing in place of standard laboratory assays in a hospital-based anticoagulation clinic with 250 active patients. The CoaguChek XS system was first validated in 253 INR samples and found to have a correlation of r = 0.945 with standard assays. Variations increased with INR readings above 3.5 and this was chosen as the cutoff for acceptance of POC INR results. POC testing was done for 1,332 clinic visits during the subsequent 6-month study. Rate of rejections of INR over 3.5 was 4.3% (95% CI 3.3-5.5%). POC testing reduced clinic visit duration by 35 min (p < 0.001, 95% CI 25-45) without cost increments to patients or the laboratory. Among 232 respondents surveyed, 87.5% (95% CI 82.5-91.5%) preferred POC INR monitoring. Rates of thrombosis and major bleeding complications were 1.2% (95% CI 0.2-3.5%) and 0.4% (95% CI 0.01-2.2%), respectively. In conclusion, provided mechanisms are in place to address increased variations of INR at higher ranges, POC testing can be successfully implemented in busy hospital-based anticoagulation clinics.

Devices for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management, part 2.

PURPOSE: The equipment and methods used for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management are discussed. SUMMARY: Over 100 million people in the United States have one or more chronic diseases, such as diabetes, hypertension, and asthma. With the goal to improve health while reducing costs and the overall health care burden, ambulatory and home monitoring by pharmacists and patients are receiving more attention. Ambulatory and home monitoring of blood pressure, cholesterol, coagulation, and weight management (including devices for assessing overweight and obese patients, heart rate monitors, and pedometers) are convenient for clinicians and patients. Such monitoring provides pharmacists with an opportunity to differentiate their practices. Studies suggest that patients who are involved in ambulatory and home monitoring take a more active role in their health and may have better adherence to a prescribed diet and medication regimens. Studies also show that ambulatory and home monitoring, if done correctly, provide clinicians with a large quantity of reliable readings for future therapeutic decisions. Devices are also a means for pharmacists to increase their provision of pharmacy services. Ambulatory monitoring is billable in many clinic settings, and the devices can be a profitable addition to prescription services. CONCLUSION: Many devices are available to assist patients and clinicians in monitoring blood pressure, lipids, coagulation, and weight management. Familiarity with the devices will help in their proper selection and use.

Self-management of oral anticoagulants with a whole blood prothrombin-time monitor in elderly patients with atrial fibrillation.

The efficacy of oral anticoagulants (OAC) in reducing the incidence of stroke in elderly patients with atrial fibrillation (AF) has been well documented. The intensity of OAC therapy and deviations in the prothrombin time (PT) are the strongest risk factor for bleeding complications in elderly patients. The aim of this study was to evaluate a more rigorous regulation of OAC by the use of a portable whole blood PT-monitor (CoaguChek) in elderly patients with AF (age 65-80 years). The study group consisted of 20 patients, of whom 17 were evaluable, which were trained to use to CoaguChek monitor and adjust their anticoagulant dose for 12 months. The control group, 20 patients matched for age, gender and the duration of OAC treatment, were tested in an anticoagulant clinic and their OAC dose was adjusted by a physician. To validate the PT-monitor results, the patients performed a total of 129 simultaneous venous blood PT tests at various time points. The correlation coefficient R(2) was 0.707 indicating the accuracy of the CoaguChek results. The self-managed patients perform more frequent measurements 46 +/- 8.9 vs. 15.7 +/- 3.1 PT tests per patient. They demonstrated a within the therapeutic range INR in 80.5% of the tests (95% confidence interval, 76.5-84.1%) as compared to 72.4% (95% confidence interval, 68.5-76.5%) in the control group (p = 0.057). The median value for all CoaguChek International Normalized Ratio (INR) recordings was within therapeutic range in the self-management group as well as in the control group. There were fewer INR results below or above the therapeutic range in the study group. None of the patients had hemorrhagic or thrombotic events during the study. Overall, the study group expressed high satisfaction from using the home monitor. We conclude that home PT monitoring and self-management of OAC are feasible in a motivated population of elderly patients with atrial fibrillation and are probably cost effective.

Assessment of patient capability to self-adjust oral anticoagulant dose: a multicenter study on home use of portable prothrombin time monitor (COAGUCHECK).

BACKGROUND AND OBJECTIVES: Self-testing and self-monitoring with portable prothrombin time (PT) monitors has been shown to be feasible and safe. However the ability of patients on chronic oral anticoagulant therapy (OAT) to self-adjust their dose without specific training has never been properly evaluated. The aims of this study were to evaluate: 1) the ability of patients on chronic OAT to self-adjust their dose without specific training; 2) the integration of a portable PT monitor (Coagucheck, Roche Diagnostics, Germany) for home use into routine patient care in anticoagulation clinics. DESIGN AND METHODS: A nested case-control study was conducted in four centers of the Italian Federation of Anticoagulation Clinics (FCSA). Patients (n=78) on stable OAT for at least 6 months (cases: 47 men, 31 women, age range: 18-75 years) were enrolled on a volunteer basis after passing an Abbreviated Mental Test and providing informed consent. After three instruction sessions on the use of Coaguchek, subjects performed the PT test at home, communicated the INR results to the Center and suggested the dose adjustment and date for next control as they thought appropriate. However, they were requested to follow the prescription made by the Center. Controls (78 subjects) matched by age (+/- 5 years), sex and therapeutic range with the cases, were selected from among those who attended the anticoagulation clinics and managed by usual care. RESULTS: When compared with the dose prescribed by the Clinic, the dose suggested by warfarin and acenocoumarol users was equal to or within +/- 6% of the mean weekly dose in 80% and 82% of suggestions, respectively. Time spent in the therapeutic range during the study was the same (80%) for cases and controls. INTERPRETATION AND CONCLUSIONS: Selected patients on chronic anticoagulant therapy can acquire a satisfactory ability for self-adjustment of OAT dose without specific training.

A primary care evaluation of three near patient coagulometers.

AIM: To compare the reliability and relative costs of three international normalised ratio (INR) near patient tests. MATERIALS: Protime (ITC Technidyne), Coaguchek (Boehringer Mannheim), and TAS (Diagnostic Testing). METHODS: All patients attending one inner city general practice anticoagulation clinic were asked to participate, with two samples provided by patients not taking warfarin. A 5 ml sample of venous whole blood was taken from each patient and a drop immediately added to the prepared Coaguchek test strip followed by the Protime cuvette. The remainder was added to a citrated bottle. A drop of citrated blood was then placed on the TAS test card and the remainder sent to the reference laboratory for analysis. Parallel INR estimation was performed on the different near patient tests at each weekly anticoagulation clinic from July to December 1997. RESULTS: 19 patients receiving long term warfarin treatment provided 62 INR results. INR results ranged from 0.8-8.2 overall and 1.0-5.7 based on the laboratory method. Taking the laboratory method as the gold standard, 12/62 results were < 2.0 and 2/62 were > 4.5. There were no statistical or clinically significant differences between results from the three systems, although all near patient tests showed slightly higher mean readings than the laboratory, and 19-24% of tests would have resulted in different management decisions based on the machine used in comparison with the laboratory INR value. The cost of the near patient test systems varied substantially. CONCLUSIONS: All three near patient test systems are safe and efficient for producing acceptable and reproducible INR results within the therapeutic range in a primary care setting. All the systems were, however, subject to operator dependent variables at the time of blood letting. Adequate training in capillary blood sampling, specific use of the machines, and quality assurance procedures is therefore essential.