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1.
Intern Med J ; 49(11): 1442-1446, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31713344

RESUMO

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.


Assuntos
Coeficiente Internacional Normatizado/instrumentação , Flebotomia/métodos , Sistemas Automatizados de Assistência Junto ao Leito/normas , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Capilares , Monitoramento de Medicamentos/instrumentação , Monitoramento de Medicamentos/normas , Feminino , Fibrinolíticos/uso terapêutico , Idoso Fragilizado , França , Instituição de Longa Permanência para Idosos , Humanos , Coeficiente Internacional Normatizado/normas , Masculino , Casas de Saúde , Estudos Prospectivos , Veias , Vitamina K/antagonistas & inibidores
2.
Rev Med Chil ; 147(10): 1273-1282, 2019 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-32186635

RESUMO

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.


Assuntos
Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito/normas , Idoso , Anticoagulantes/uso terapêutico , Capilares , Chile , Monitoramento de Medicamentos/instrumentação , Monitoramento de Medicamentos/normas , Feminino , Humanos , Coeficiente Internacional Normatizado/normas , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Reprodutibilidade dos Testes , Tromboplastina/uso terapêutico
3.
Scand J Clin Lab Invest ; 77(2): 115-121, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28150507

RESUMO

Regular measurement of prothrombin time as an international normalized ratio PT (INR) is mandatory for optimal and safe use of warfarin. Scandinavian evaluation of laboratory equipment for primary health care (SKUP) evaluated the microINR portable coagulometer (microINR®) (iLine Microsystems S.L., Spain) for measurement of PT (INR). Analytical quality and user-friendliness were evaluated under optimal conditions at an accredited hospital laboratory and at two primary health care centres (PHCCs). Patients were recruited at the outpatient clinic of the Laboratory of Medical Biochemistry, St Olav's University Hospital, Trondheim, Norway (n = 98) and from two PHCCs (n = 88). Venous blood samples were analyzed under optimal conditions on the STA-R®Evolution with STA-SPA + reagent (Stago, France) (Owren method), and the results were compared to capillary measurements on the microINR®. The imprecision of the microINR® was 6% (90% CI: 5.3-7.0%) and 6.3% (90% CI: 5.1-8.3) in the outpatient clinic and PHCC2, respectively for INR ≥2.5. The microINR® did not meet the SKUP quality requirement for imprecision ≤5.0%. For INR <2.5 at PHCC2 and at both levels in PHCC1, CV% was ≤5.0. The accuracy fulfilled the SKUP quality goal in both outpatient clinic and PHCCs. User-friendliness of the operation manual was rated as intermediate, defined by SKUP as neutral ratings assessed as neither good nor bad. Operation facilities was rated unsatisfactory, and time factors satisfactory. In conclusion, quality requirements for imprecision were not met. The SKUP criteria for accuracy was fulfilled both at the hospital and at the PHCCs. The user-friendliness was rated intermediate.


Assuntos
Automação Laboratorial/normas , Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito/normas , Tempo de Protrombina/instrumentação , Análise de Variância , Anticoagulantes/farmacologia , Automação Laboratorial/instrumentação , Coagulação Sanguínea/efeitos dos fármacos , Humanos , Laboratórios Hospitalares , Noruega , Reprodutibilidade dos Testes , Varfarina/farmacologia
4.
Ann Pharmacother ; 50(8): 645-8, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27199494

RESUMO

BACKGROUND: Despite the emergence of several new oral anticoagulants, warfarin remains a widely used form of anticoagulation that continues to have a role in the treatment of cardiac and thrombotic conditions. OBJECTIVE: The goal of this study was to evaluate whether the R-T estimation, an equation developed in a previous study, was a valid clinical tool in managing patients' warfarin therapy in an anticoagulation clinic in lieu of obtaining a venipuncture international normalized ratio (INR) secondary to a high CoaguChek XS (CXS) INR. METHODS: This study used a randomized double-blind method to compare the clinical decisions made using venipuncture or CXS machine and recorded the INR, percentage dose change, time to clinical decision from check-in, and scheduled follow-up. RESULTS: In the analysis of the difference in percentage dose change, a 1.0% (95% CI = -0.78 to 2.68; P = 0.27) difference was observed overall, and a 1.2% (95% CI = -0.59 to 2.95; P = 0.18) difference was observed in the 4 to 5.9 subgroup. Clinical decisions were reached 17 minutes faster (95% CI = 11-24; P < 0.001) overall and 17 minutes faster (95% CI = 10-24; P < 0.001) in the 4 to 5.9 subgroup. Scheduled follow-up was 0.38 weeks sooner (95% CI = 0.01-0.67; P = 0.014) overall and 0.36 weeks sooner (95% CI = 0-0.66; P = 0.041) in the 4 to 5.9 subgroup. CONCLUSIONS: The results of this study support the use of the R-T estimation for correction of INR values obtained using the CXS meter when the INR is in the range of 4 to 5.9. This correction will allow clinics using this device to more efficiently manage patients taking warfarin.


Assuntos
Anticoagulantes/administração & dosagem , Coagulação Sanguínea/efeitos dos fármacos , Monitoramento de Medicamentos/métodos , Coeficiente Internacional Normatizado/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Varfarina/administração & dosagem , Administração Oral , Adulto , Anticoagulantes/efeitos adversos , Anticoagulantes/uso terapêutico , Agendamento de Consultas , Tomada de Decisões , Método Duplo-Cego , Monitoramento de Medicamentos/instrumentação , Monitoramento de Medicamentos/normas , Feminino , Florida , Humanos , Coeficiente Internacional Normatizado/instrumentação , Coeficiente Internacional Normatizado/normas , Masculino , Pessoa de Meia-Idade , Flebotomia , Sistemas Automatizados de Assistência Junto ao Leito/normas , Reprodutibilidade dos Testes , Fatores de Tempo , Varfarina/efeitos adversos , Varfarina/uso terapêutico
5.
Clin Lab ; 61(7): 653-60, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26299062

RESUMO

BACKGROUND: Coagulation testing is widely applied clinically, and laboratories increasingly demand automated coagulation analyzers with short turn-around times and high-throughput. The purpose of this study was to evaluate the performance of the Sysmex CS-5100 automated coagulation analyzer for routine use in a clinical laboratory. METHODS: The prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (APTT), fibrinogen (Fbg), and D-dimer were compared between the Sysmex CS-5100 and Sysmex CA-7000 analyzers, and the imprecision, comparison, throughput, STAT function, and performance for abnormal samples were measured in each. RESULTS: The within-run and between-run coefficients of variation (CV) for the PT, APTT, INR, and D-dimer analyses showed excellent results both in the normal and pathologic ranges. The correlation coefficients between the Sysmex CS-5100 and Sysmex CA-7000 were highly correlated. The throughput of the Sysmex CS-5100 was faster than that of the Sysmex CA-7000. There was no interference at all by total bilirubin concentrations and triglyceride concentrations in the Sysmex CS-5100 analyzer. CONCLUSIONS: We demonstrated that the Sysmex CS-5100 performs with satisfactory imprecision and is well suited for coagulation analysis in laboratories processing large sample numbers and icteric and lipemic samples.


Assuntos
Testes de Coagulação Sanguínea/instrumentação , Coagulação Sanguínea , Automação Laboratorial , Biomarcadores/sangue , Desenho de Equipamento , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Humanos , Coeficiente Internacional Normatizado/instrumentação , Teste de Materiais , Tempo de Tromboplastina Parcial/instrumentação , Valor Preditivo dos Testes , Tempo de Protrombina/instrumentação , Reprodutibilidade dos Testes , Fatores de Tempo
6.
Can J Anaesth ; 62(3): 258-64, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25666228

RESUMO

PURPOSE: To investigate the reliability of a point-of-care device, the HEMOCHRON(®) Jr. Signature, for measuring the international normalized ratio (INR) during the three surgical phases of liver transplantation. METHODS: A retrospective review was performed on patients undergoing liver transplantation during July to December 2013. Thirty-one patients who had simultaneous laboratory and point-of-care INR readings from each phase of liver transplant surgery (paleohepatic, anhepatic, and neohepatic) were eligible for inclusion. Bland-Altman analysis, Spearman's rank correlation, and four quadrant plots were used to compare INR results from the point-of-care device (pocINR) with those from the laboratory (labINR). RESULTS: Based on the Bland-Altman analysis, mean biases (95% prediction interval) were 0.10 (0.03 to 0.17), 0.19 (0.12 to 0.27), and 0.21 (0.01 to 0.43) for the paleohepatic, anhepatic, and neohepatic phases, respectively. The pocINR device showed a systematic underestimation of the labINR. The Spearman's rank correlation coefficients (95% confidence interval [CI]) were: Ρ = 0.90 (95% CI 0.80 to 0.95); Ρ = 0.92 (95% CI 0.71 to 0.93); and Ρ = 0.71 (95% CI 0.46 to 0.85), respectively. Direction-of-change analysis between the paleohepatic to anhepatic and the anhepatic to neohepatic phases showed strong concordance of 84% and, also considering the small bias between the measurements, supports the use of the pocINR device in the clinical management of liver transplant surgery. CONCLUSION: Point-of-care INR was accurate prior to hepatic reperfusion, but reliability decreased in the neohepatic phase.


Assuntos
Coeficiente Internacional Normatizado/instrumentação , Transplante de Fígado , Sistemas Automatizados de Assistência Junto ao Leito , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos
7.
Semin Thromb Hemost ; 40(1): 115-20, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24381152

RESUMO

Warfarin dosing relies on accurate measurements of international normalized ratio (INR), which is calculated from the prothrombin time (PT), International Sensitivity Index international sensitivity index (ISI) of the thromboplastin, and the geometric mean of normal PT (MNPT). However, ISI assignments of certain reagent/instrument combinations are frequently unavailable, especially when the reagent and instrument are not from the same manufacturer. The effort to be in compliance with widely endorsed Clinical and Laboratory Standards Institute (CLSI) guidelines by locally verifying or assigning an ISI to an unsupported reagent/instrument combination is further hindered by the lack of US Food and Drug Administration (FDA)-approved certified plasmas designated for a particular reagent/instrument combination. The objectives of the study include development of a process to verify/assign ISI and MNPT of a single thromboplastin reagent from one manufacturer across multiple instruments including several from another manufacturer and across several campuses of a single institution, the Mayo Clinic. In this study, RecombiPlasTin 2G (R2G), was evaluated on the ACL TOP 700 (IL), STA-R Evolution, STA Compact, and STA Satellite. Random normal donor samples (n = 25) were used to verify/assign MNPT. A subset of the normal donors (n = 8) and 13 warfarin pools (INR range: 1.3-3.9), created from stable warfarin patient plasma, were used for ISI verification/assignment. The manufacturer's assigned ISI was first verified on the ACL TOP 700 (reference method), then assigned on three unsupported instruments using orthogonal regression analysis. The MNPT and manufacturer assigned ISI (11.0, 0.95) were verified on the ACL TOP 700 and subsequently assigned on the STA-R Evolution (11.6, 1.04); STA Compact (11.5, 1.02); and STA Satellite (10.9, 0.99). Linear correlations of the INR results from all the four instruments demonstrated an r2 > 0.99. This process provides a reproducible approach to assigning ISIs on unsupported reagent/instrument combinations. Our data also confirm that ISIs of the same PT reagent differ significantly on different instruments, thus confirming the requirement for evaluations and validation of ISIs for different reagent/instrument combinations.


Assuntos
Anticoagulantes , Doadores de Sangue , Coeficiente Internacional Normatizado , Tempo de Protrombina , Varfarina , Anticoagulantes/administração & dosagem , Anticoagulantes/farmacocinética , Feminino , Humanos , Coeficiente Internacional Normatizado/instrumentação , Coeficiente Internacional Normatizado/métodos , Coeficiente Internacional Normatizado/normas , Masculino , Tempo de Protrombina/instrumentação , Tempo de Protrombina/métodos , Tempo de Protrombina/normas , Estados Unidos , Varfarina/administração & dosagem , Varfarina/farmacocinética
8.
BMC Pediatr ; 14: 179, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-25008798

RESUMO

BACKGROUND: Neonates routinely receive vitamin K to prevent vitamin K deficiency bleeding, which is associated with a high mortality rate and a high frequency of neurological sequelae. A coagulation screening test might be necessary to detect prophylactic failure or incomplete prophylaxis. However, venous access and the volume of blood required for such testing can be problematic. CoaguChek XS is a portable device designed to monitor prothrombin time while only drawing a small volume of blood. Although the device is used in adults and children, studies have not been performed to evaluate its clinical utility in neonates, and the reference value is unknown in this population. The objectives of the present study were to determine the reference intervals (RIs) for international normalized ratio (INR) using the CoaguChek XS by capillary puncture in healthy term neonates, to evaluate factors that correlate with INR, and to evaluate the device by assessing its ease of use in clinical practice. METHODS: This study included 488 healthy term neonates born at a perinatal center between July 2012 and June 2013. The INRs determined by CoaguChek XS were measured in 4-day-old neonates. RESULTS: The enrolled neonates were orally administered vitamin K 6-12 h after birth. A RI for INRs in 4-day-old neonates was established using the CoaguChek XS with a median value of 1.10 and a range of 0.90-1.30. A significant difference in the INR was noted between male (median value, 1.10; RI, 0.90-1.30) and female (median value, 1.10; RI, 0.90-1.24) neonates (p = 0.049). The INR was found to correlate with gestational age, birth weight, and hematocrit value. CONCLUSIONS: The CoaguChek XS device is safe, fast, and convenient for performing INR assays in neonates. Our study is the first to establish a RI for INRs that were measured using the CoaguChek XS in healthy term neonates.


Assuntos
Monitoramento de Medicamentos/instrumentação , Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Tempo de Protrombina/instrumentação , Sangramento por Deficiência de Vitamina K/prevenção & controle , Vitamina K/uso terapêutico , Vitaminas/uso terapêutico , Administração Oral , Esquema de Medicação , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Recém-Nascido , Coeficiente Internacional Normatizado/métodos , Coeficiente Internacional Normatizado/normas , Modelos Lineares , Masculino , Estudos Prospectivos , Tempo de Protrombina/métodos , Tempo de Protrombina/normas , Valores de Referência , Resultado do Tratamento , Sangramento por Deficiência de Vitamina K/sangue
9.
Br J Neurosurg ; 28(1): 29-33, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24313307

RESUMO

INTRODUCTION: With the increased use of oral anticoagulation with vitamin K antagonists, emergency physicians encounter a growing number of patients requiring a rapid reversal of anticoagulant effects in order to perform urgent surgical procedures. Initiation of these procedures can be delayed because the coagulation status has to be assessed through examination of blood samples in central laboratories (CL). This delay may lead to negative effects, especially in potentially life-threatening conditions such as intracranial haemorrhage. Point-of-care (POC) devices for assessment of international normalized ratio (POC INR) have improved the management of anticoagulation therapy in the outpatient setting. The use of these devices may also have beneficial effects in the treatment of anticoagulated patients requiring urgent neurosurgical procedures. The primary aim of this study was to analyse the potential of POC-guided assessment of INR to reduce time to potentially life-saving neurosurgery in this setting. Feasibility and accuracy as well as the gain of time through the use of this device were analysed. MATERIALS AND METHODS: The POC coagulometer CoaguChek XS(®) was used in 17 patients with a history of anticoagulant use and a condition requiring urgent anticoagulant reversal prior to neurosurgical procedures (burr-hole trepanation: n = 8, craniotomy: n = 7, laminectomy: n = 2). RESULTS: No technical difficulties occurred and rapid assessment of INR was achieved in all cases within 2 min. POC INR values correlated well with CL INR assessment with a mean INR deviation of 0.036 ± 0.12. The mean gain of time through the use of the POC INR device compared with CL assessment of INR was 47 ± 6 min (range: 37-61 min). CONCLUSION: Our initial experiences with a POC INR device in anticoagulated patients undergoing urgent neurosurgical procedures demonstrate that its use may contribute to an improved management of these patients.


Assuntos
Coagulação Sanguínea/fisiologia , Equipamentos e Provisões/normas , Coeficiente Internacional Normatizado/instrumentação , Procedimentos Neurocirúrgicos/normas , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/sangue , Anticoagulantes/farmacologia , Estudos de Viabilidade , Feminino , Humanos , Coeficiente Internacional Normatizado/métodos , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Fatores de Tempo
10.
Mayo Clin Proc ; 99(7): 1091-1100, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38661594

RESUMO

OBJECTIVE: To standardize international normalized ratio (INR) measurements and improve data integrity by enabling electronic result transmission for warfarin monitoring, two point-of-care (POC) devices were evaluated against an internal plasma INR reference method. METHODS: A multicenter study was pursued (January 24, 2022, through October 19, 2022) to compare concordance of two commercially available POC devices, Coag-Sense PT2 Meter (Coag-Sense) and CoaguChek XS Pro and Plus devices (CoaguChek), against an internal plasma INR method among patients treated with warfarin. Bias and linear regression analysis were assessed for these devices including dosing decision accuracy compared with plasma INR reference. RESULTS: Two hundred ninety-nine patients treated with warfarin across three Mayo Clinic sites agreed to participate. Atrial fibrillation (n=191, 63.9%), venous thromboembolism (n=65; 21.7%), and heart valve prosthesis (n=46; 15.4%) were common anticoagulant indications with a 2.5 INR target for 280 (93.6%) of patients. For the CoaguChek devices, 243 (81.3%) of values fell within 0.2 INR units with plasma INR referent and 285 (95.3%) within 0.4 units (R2=0.93). For the Coag-Sense device, 102 (34.1%) of values fell within 0.2 INR units and 180 (60.2%) within 0.4 INR units of plasma INR values, (R2=0.83; P<.0001). Using the plasma INR as the gold standard, appropriate dosing recommendations would have occurred for 292 (97.7%) of the CoaguChek and 244 (81.6%) of the Coag-Sense results. CONCLUSION: Compared with a plasma referent, INR values obtained from the CoaguChek devices exhibited less systematic bias compared with Coag-Sense measures. This translates to a greater percentage of concordant management decisions between POC and laboratory INR methods.


Assuntos
Anticoagulantes , Monitoramento de Medicamentos , Coeficiente Internacional Normatizado , Sistemas Automatizados de Assistência Junto ao Leito , Varfarina , Humanos , Coeficiente Internacional Normatizado/instrumentação , Coeficiente Internacional Normatizado/normas , Masculino , Feminino , Sistemas Automatizados de Assistência Junto ao Leito/normas , Anticoagulantes/administração & dosagem , Varfarina/administração & dosagem , Varfarina/uso terapêutico , Monitoramento de Medicamentos/métodos , Monitoramento de Medicamentos/instrumentação , Pessoa de Meia-Idade , Idoso , Fibrilação Atrial/tratamento farmacológico , Tromboembolia Venosa/sangue
11.
J Card Surg ; 28(3): 254-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23578221

RESUMO

AIM: To compare the international normalised ratio (INR) value of patients evaluated using the CoaguChek XS versus conventional laboratory methods, in the period after open-heart surgery for mechanical valve replacement until a therapeutic range is achieved using vitamin K antagonists (VKA) together with low molecular weight heparin (LMWH). METHODS: One hundred and five patients undergoing open-heart surgery for mechanical valve replacement were enrolled. Blood samples were collected from patients before surgery, and on the second and fifth postoperative days, simultaneously for both the point of care device and conventional laboratory techniques. Patients were administered VKA together with LMWH at therapeutic doses (enoxaparin 100 IU/kg twice daily) subcutaneously, until an effective range was achieved on approximately the fifth day after surgery. RESULTS: The mean INR values using the CoaguChek XS preoperatively and on the second and fifth days postoperatively were 1.20 (SD ± 0.09), 1.82 (SD ± 0.45), and 2.55 (SD ± 0.55), respectively. Corresponding results obtained using conventional laboratory techniques were 1.18 (SD ± 0.1), 1.81 (SD ± 0.43), and 2.51 (SD ± 0.58). The correlation coefficient was r = 0.77 preoperatively, r = 0.981 on postoperative day 2, and r = 0.983 on postoperative day 5. DISCUSSION: Results using the CoaguChek XS Handheld Coagulation Analyzer correlated strongly with conventional laboratory methods, in the bridging period between open-heart surgery for mechanical valve replacement and the achievement of a therapeutic range on warfarin and LMWH.


Assuntos
Anticoagulantes/administração & dosagem , Implante de Prótese de Valva Cardíaca , Coeficiente Internacional Normatizado/instrumentação , Complicações Intraoperatórias/sangue , Vitamina K/antagonistas & inibidores , Varfarina/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Esquema de Medicação , Quimioterapia Combinada , Enoxaparina/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
12.
Clin Chem Lab Med ; 50(9): 1611-20, 2012 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-22962222

RESUMO

BACKGROUND: The reasons for discrepancies between International Normalized Ratio (INR) results determined by point-of-care-instruments and laboratory measurements are not fully understood. In this study we investigated whether different levels of coagulation factors in the plasma of patients can explain some of the systematic and/or random parts of the difference in INR between the instruments. METHODS: Blood samples were collected at four different patient visits from each of 34 outpatients on warfarin treatment. INR was determined on a laboratory instrument (STA Compact(®)) and on three point-of-care instruments (Simple Simon(®)PT, CoaguChek(®)XS and INRatio™). In addition, the level of fibrinogen, coagulation factors II, V, VII and X was determined. INR instruments were compared in pairs. Simple linear regressions as well as multiple linear regressions and nested ANOVA analyses were used to examine the data. RESULTS: The coagulation factors, especially fibrinogen, factors II and VII, could explain between 16% and 45% of the total variance of the differences in INR between instruments dependent on instruments compared. After correction for factors no systematic difference was seen for four of the six comparisons and the between- and within-subject variation of the differences were reduced by up to 69% and 52%, respectively. CONCLUSIONS: By correcting for the appropriate coagulation factors, especially the systematic differences, but also the between- and within-subject variation of the differences between instruments, were reduced. This indicates that different levels of coagulation factors in the plasma of the patients play an important role in explaining discrepancies between INR instruments.


Assuntos
Fatores de Coagulação Sanguínea/análise , Coeficiente Internacional Normatizado/instrumentação , Análise de Variância , Anticoagulantes/química , Anticoagulantes/uso terapêutico , Humanos , Laboratórios Hospitalares , Modelos Lineares , Sistemas Automatizados de Assistência Junto ao Leito , Trombose/tratamento farmacológico , Varfarina/química , Varfarina/uso terapêutico
13.
Comput Math Methods Med ; 2022: 5975228, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35222684

RESUMO

The mechanical heart valve is a crucial solution for many patients. However, it cannot function on the state of blood as human tissue valves. Thus, people with mechanical valves are put under anticoagulant therapy. A good measurement of the state of blood and how long it takes blood to form clots is the prothrombin time (PT); moreover, it is an indicator of how well the anticoagulant therapy is, and of whether the response of the patient to the drug is as needed. For a more specific standardized measurement of coagulation time, an international normalized ratio (INR) is established. Clinical testing of INR and PT is relatively easy. However, it requires the patient to visit the clinic for evaluation purposes. Many techniques are therefore being developed to provide PT and INR self-testing devices. Unfortunately, those solutions are either inaccurate, complex, or expensive. The present work approaches the design of an anticoagulation self-monitoring device that is easy to use, accurate, and relatively inexpensive. Hence, a two-channel polymethyl methacrylate-based microfluidic point-of-care (POC) smart device has been developed. The Arduino based lab-on-a-chip device applies optical properties to a small amount of blood. The achieved accuracy is 96.7%.


Assuntos
Coeficiente Internacional Normatizado/instrumentação , Dispositivos Lab-On-A-Chip , Testes Imediatos , Tempo de Protrombina/instrumentação , Anticoagulantes/uso terapêutico , Biologia Computacional , Desenho de Equipamento , Próteses Valvulares Cardíacas , Humanos , Coeficiente Internacional Normatizado/métodos , Coeficiente Internacional Normatizado/estatística & dados numéricos , Dispositivos Lab-On-A-Chip/estatística & dados numéricos , Dispositivos Ópticos/estatística & dados numéricos , Testes Imediatos/estatística & dados numéricos , Polimetil Metacrilato , Tempo de Protrombina/métodos , Tempo de Protrombina/estatística & dados numéricos , Autoteste
14.
Nat Commun ; 13(1): 831, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35149711

RESUMO

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.


Assuntos
Testes de Coagulação Sanguínea/métodos , Coeficiente Internacional Normatizado/métodos , Tempo de Protrombina/métodos , Smartphone , Trombose/diagnóstico , Algoritmos , Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Testes de Coagulação Sanguínea/instrumentação , Hemorragia , Humanos , Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Tempo de Protrombina/instrumentação , Varfarina/farmacologia
16.
Ann Pharmacother ; 45(7-8): e40, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21712509

RESUMO

OBJECTIVE: To report 2 cases in which point-of-care international normalized ratios (INRs) in dabigatran-treated patients were inaccurate. CASE SUMMARY: A 59-year-old woman with paroxysmal atrial fibrillation was started on warfarin. After 3 days, warfarin was discontinued, and the decision was made to switch to dabigatran 150 mg twice a day, which was started 2 days after the warfarin was discontinued. As treatment was being converted from warfarin to dabigatran therapy, the woman's primary care physician referred her to our anticoagulation clinic, where her point-of-care INR was 7.2. A laboratory INR performed approximately 30 minutes later was 1.7. Several repeat point-of-care INRs were elevated and discordant with the laboratory INRs. A second patient, a 52-year-old man, was started on dabigatran after an ablation procedure, as a bridge to warfarin. Approximately 16 hours after a single dose of dabigatran etexilate 150 mg, the point-of-care INR was 1.6. DISCUSSION: Dabigatran etexilate is an oral direct thrombin inhibitor that is approved for use in thromboprophylaxis of atrial fibrillation and deep vein thrombosis. Dabigatran's predictable pharmacokinetic profile allows for a fixed-dose regimen without the need for coagulation monitoring. In certain clinical situations (eg, switching treatment between dabigatran and warfarin), INR testing is performed as part of routine clinical care. During the development program for dabigatran, laboratory testing of INR was performed, with INRs at therapeutic concentrations of dabigatran ranging from 1.1 to 1.7. Supratherapeutic concentrations of dabigatran elevated the INR to slightly higher levels, between 1.7 and 2.4. Even at extremely high dabigatran concentrations, the INR was generally in the range of 2.3-3.5. CONCLUSIONS: We advocate laboratory INR testing with simultaneous assessment of the activated partial thromboplastin time in patients who are receiving or who have recently received dabigatran. A prospective evaluation assessing the accuracy of the commonly used point-of-care INR devices in patients receiving dabigatran would confirm our findings with respect to this device and determine whether our findings extend to other commonly used devices.


Assuntos
Antitrombinas/uso terapêutico , Benzimidazóis/uso terapêutico , Coeficiente Internacional Normatizado , Sistemas Automatizados de Assistência Junto ao Leito , beta-Alanina/análogos & derivados , Antitrombinas/efeitos adversos , Fibrilação Atrial/sangue , Fibrilação Atrial/tratamento farmacológico , Benzimidazóis/efeitos adversos , Dabigatrana , Monitoramento de Medicamentos , Feminino , Humanos , Coeficiente Internacional Normatizado/instrumentação , Masculino , Pessoa de Meia-Idade , Tempo de Tromboplastina Parcial , Piridinas/efeitos adversos , Piridinas/uso terapêutico , Reprodutibilidade dos Testes , Procedimentos Desnecessários , beta-Alanina/efeitos adversos , beta-Alanina/uso terapêutico
17.
J Heart Valve Dis ; 20(5): 518-25, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22066355

RESUMO

BACKGROUND AND AIM OF THE STUDY: In this single-center French study, the conventional management of patients receiving vitamin K antagonists (VKAs) was compared with an International Normalized Ratio (INR) self-testing program. The aim was to determine the reliability of self-testing devices, and to estimate the variability of the self-measured INR within the therapeutic and target range. METHODS: A total of 206 patients who had undergone valve replacement with a mechanical prosthesis, with or without myocardial revascularization, between May 2004 and September 2007 was randomized into two groups. Group 1 patients (n = 103) underwent INR monitoring at a laboratory, while Group 2 patients (n = 103) underwent self-testing INR using either the CoaguChek (Roche) (Group 2A; n = 55) or INRatio (Hemosense) (Group 2B; n = 48) system. Patients in Group 1 underwent at least once-monthly INR measurement, while those in Group 2 carried out once-weekly self-testing, and also underwent once-monthly INR measurement at the laboratory. The large majority of patients (97.9%) were treated with fluindione. RESULTS: The mean follow up period was 49.0 +/- 10.3 weeks. Self-testing was reliable, with a correlation coefficient between device- and laboratory-measured INRs of 0.80 [CI: 0.78, 0.82] (p < 0.0001). The proportion of time spent within the INR target range was significantly higher for Group 2 (61.5 +/- 19.3% versus 55.5 +/- 19.9%; p < 0.05), while the absolute mean deviation of INR from the target range was higher in Group 1 (60.1 +/- 70.2% versus 47.4 +/- 51.5%). Adverse events were reported by seven patients in Group 1, but by no patients in Group 2 (p < 0.01). CONCLUSION: INR self-testing devices are reliable and beneficial. Moreover, INR self-monitoring allows an enhanced stability within a target range, and also helps to prevent serious postoperative complications.


Assuntos
Próteses Valvulares Cardíacas , Serviços Hospitalares de Assistência Domiciliar , Coeficiente Internacional Normatizado/instrumentação , Monitorização Fisiológica/instrumentação , Autocuidado , Estudos de Viabilidade , Feminino , França , Doenças das Valvas Cardíacas/cirurgia , Humanos , Coeficiente Internacional Normatizado/métodos , Pessoa de Meia-Idade , Monitorização Fisiológica/métodos , Qualidade de Vida
18.
J Med Assoc Thai ; 94 Suppl 1: S89-93, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21721433

RESUMO

BACKGROUND: There are limited data concerning accuracy of portable coagulometer in emergency setting. OBJECTIVE: To evaluate the accuracy of the CoaguChek XS international normalized ratio (INR) monitor compared to the standard laboratory method in emergency department. MATERIAL AND METHOD: Emergency room patients who required coagulation test were recruited. Parallel INR measurements between portable coagulometer and standard laboratory were performed. RESULTS: Fifty-five patients with a mean age of 59.1 +/- 15.7 years (20-87) were included. Men constituted 56.4%. Indications for testing were as follows: acute stroke 72.7%; abnormal bleeding 7.3%; taking anticoagulant 7.3%; and others 12.7%. Mean time +/- SD used from blood drawn to INR result report was 65.02 +/- 24.5 minutes for standard laboratory and 1 minute for portable coagulometer. Mean difference of INR result from portable coagulometer and standard laboratory was 0.02 +/- 0.13 and an excellence correlation between INR (r = 0.969) was demonstrated. There was no significant difference between the INR value from the two methods (p = 0.34). CONCLUSION: The use of portable coagulometer (CoaguChek XS) in emergency setting was accurate and required less time. Acute ischemic stroke patients are likely to benefit from a timely clinical decision making for thrombolysis medication.


Assuntos
Transtornos da Coagulação Sanguínea/diagnóstico , Técnicas de Laboratório Clínico , Coeficiente Internacional Normatizado/instrumentação , Coeficiente Internacional Normatizado/normas , Sistemas Automatizados de Assistência Junto ao Leito/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Serviço Hospitalar de Emergência , Feminino , Hospitais de Ensino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
19.
Compend Contin Educ Dent ; 32(5): E91-4, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23738939

RESUMO

OBJECTIVES: This study aimed to teach dental students to use an INRatio® (HemoSense) device, to apply the results to patients, and to evaluate the outcomes. DESIGN: This was a retrospective convenience data study that used student surveys. SETTING: The research was conducted at The Ohio State University College of Dentistry Geriatric Dental Program in Columbus, Ohio. PARTICIPANTS: A total of 105 senior dental students participated in an INRatio training program. METHODS: The instructions involved the following: 1) a table showing INRatio protocol and dental procedures versus international normalized ratio (INR) guidelines; 2) an online technique training course, 3) a trial INRatio test on another senior dental student; and 4) INRatio for a dental patient. MAIN OUTCOMES: The clinical outcomes including INR values were a retrospective convenience data study. Instructional outcomes were obtained from student surveys. RESULTS: A total of 79% of students indicated they would use portable INR testing in their future practices; however, 73% of students had difficulty obtaining an adequate blood sample. All patient surgical procedures were completed successfully without serious complications. CONCLUSIONS: This study indicates the INRatio analysis can be included in dental student training, providing safe, efficient, and successful patient care. Difficulty obtaining blood samples suggests the need for extra training, additional clinical experience, and INR devices requiring smaller blood samples.


Assuntos
Assistência Odontológica , Educação em Odontologia , Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Estudantes de Odontologia , Idoso , Anticoagulantes/uso terapêutico , Perda Sanguínea Cirúrgica , Coleta de Amostras Sanguíneas , Instrução por Computador , Feminino , Seguimentos , Humanos , Masculino , Procedimentos Cirúrgicos Menores/métodos , Sistemas On-Line , Procedimentos Cirúrgicos Bucais/métodos , Hemorragia Pós-Operatória/etiologia , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , Ensino/métodos , Materiais de Ensino , Varfarina/uso terapêutico
20.
Int J Lab Hematol ; 43(5): 1191-1197, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33460254

RESUMO

INTRODUCTION: We evaluated the analytical performance of CoaguChek Pro II (Roche Diagnostics GmbH, Mannheim, Germany), a new point-of-care device measuring the international normalized ratio (INR) values, in comparison with CoaguChek XS Plus (Roche Diagnostics GmbH) and STA-R Max using STA-Neoplastine CI Plus (Diagnostica Stago SAS, Asnières-sur-Seine, France). METHODS: The precision of Pro II was analyzed, according to the Clinical and Laboratory Standards Institute guidelines (CLSI POCT14-A2 and EP15-A3). In 105 clinical samples, the Pro II INR values were compared with those of XS Plus and STA-R Max using STA-Neoplastine CI Plus (CLSI EP09-A3 and EP35). We also compared the Pro II INR values between capillary blood (CB) and venous blood (VB; CLSI EP35). RESULTS: The precision of Pro II was acceptable (within-run and between-run CV%: 2.71% and 3.28% at normal level; 1.52% and 4.47% at abnormal level, respectively). The Pro II INR values showed very high correlation and almost perfect agreement with those of XS Plus and STA-R Max using STA-Neoplastine CI Plus (r = .97 and κ = .94; r = .95 and κ = .91). The mean difference between Pro II and STA-R Max using STA-Neoplastine CI Plus increased as INR values increased, with 60% of samples showing differences >0.5 in the supratherapeutic range. The Pro II INR values showed very high correlation between CB and VB (r = .98). CONCLUSION: Pro II INR values are accurate and reliable using both CB and VB; however, they should be confirmed by laboratory analyzers in the supratherapeutic range.


Assuntos
Coagulação Sanguínea , Coeficiente Internacional Normatizado/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Testes de Coagulação Sanguínea/instrumentação , Testes de Coagulação Sanguínea/métodos , Feminino , Humanos , Coeficiente Internacional Normatizado/métodos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
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