Polymethyl Methacrylate-Based Smart Microfluidic Point-of-Care Testing of Prothrombin Time and International Normalized Ratio through Optical Detection.

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%.

Micro-mechanical blood clot testing using smartphones.

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.

Performance evaluation of coaguchek pro II in comparison with coaguchek XS plus and sta-r Max using a sta-neoplastine CI plus.

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.

Patients' satisfaction associated with portable coagulometers for warfarin monitoring: a cross-sectional study.

BACKGROUND: The use of point-of-care (POC) coagulometers for monitoring patients on vitamin K antagonist (VKA) treatment makes international normalised ratio (INR) results immediately available. The aim of this study was to compare patients' satisfaction with VKA treatment in two settings characterised by distinct ways of monitoring: POC INR versus laboratory INR. MATERIALS AND METHODS: We recruited adult patients on long-term warfarin treatment (July 2017-February 2018) from the Anticoagulation Clinics at five district health centres (namely Cospicua, Floriana, Mosta, Qormi, Rabat-POC INR) and at Mater Dei Hospital (Msida - Laboratory INR) in Malta. We administered two psychometric questionnaires: the Duke Anticoagulation Satisfaction Scale (DASS) (range 25-175, lower scores corresponding to higher satisfaction) and the Perception of Anticoagulation Treatment Questionnaire (PACT-Q2) (range 0-100, higher scores corresponding to higher satisfaction). RESULTS: We analysed 313 questionnaires (POC INR n=159, laboratory INR n=154). In the POC INR cohort, median age was 72 years and 59.1% were males; in the laboratory INR cohort, median age was 70.5 years and 46.1% were males. The POC INR cohort obtained significantly lower overall DASS score (p<0.001) and significantly higher PACT-Q2 scores (p<0.001 for the subscale "convenience"; p=0.039 for the subscale "anticoagulant treatment satisfaction") than the laboratory INR cohort. In multiple regression analysis, the use of POC coagulometers was significantly associated with the overall DASS score (p=0.013) and the PACT-Q2 convenience score (p=0.012). DISCUSSION: Patients on warfarin treatment were generally satisfied. Patients monitored with the POC INR with a dedicated time slot reported less inconvenience and burdens and better psychological impact than patients monitored with the traditional laboratory INR.

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.

Fiabilidad del coagulómetro portátil en pacientes con ictus isquémico agudo tratados con fibrinólisis intravenosa / Reliability of point-of-care coagulometer measurements in patients with acute ischaemic stroke receiving intravenous fibrinolysis

INTRODUCCIÓN: La eficacia de la fibrinólisis intravenosa como tratamiento en el ictus isquémico agudo depende de la rapidez en su administración. Para reducir el riesgo de complicaciones hemorrágicas existen contraindicaciones, como una INR ≥ 1,7. Nuestro objetivo fue determinar la fiabilidad del valor de INR obtenido mediante el coagulómetro portátil (CP) CoaguChek XS ® (CPINR) frente al resultado del laboratorio (LINR). MÉTODOS: Estudio retrospectivo observacional de pacientes consecutivos con ictus isquémico tratados con fibrinólisis intravenosa en nuestro centro durante 4 años. La INR fue medida con CP y en el laboratorio. Se compararon ambos valores mediante t de Student para datos apareados y, tomando como referencia la LINR, se realizó análisis ROC para determinar la CPINR con mayor valor predictivo. RESULTADOS: Analizamos a 210 pacientes, con edad media 74,3 ± 11,5 años, y 18 (8,6%) tomaban anticoagulantes orales antivitamina K. Se compararon LINR y CPINR sin evidenciarse diferencias significativas (diferencia LINR-CPINR -0,001 ± 0,085; p = 0,82). En el análisis por subgrupos: para pacientes con anticoagulantes orales (diferencia LINR-CPINR 0,001 ± 0,081; p = 0,42) y para LINR ≤ 1,2 (diferencia LINR-CPINR -0,008 ± 0,081; p = 0,16) ambas técnicas fueron concordantes, mientras que para LINR >1,2, CPINR infraestimó la INR (diferencia LINR-CPINR 0,058 ± 0,095; p = 0,01). Mediante análisis ROC una CPINR < 1,6 fue el punto de corte más sensible y específico para seleccionar pacientes tratables con fibrinólisis intravenosa (LINR < 1,7). CONCLUSIONES: El CP en el código ictus tiene una buena concordancia con el laboratorio. Este estudio indica que en nuestro centro una CPINR < 1,6 es el mejor umbral para predecir una LINR < 1,7. La validación de la CPINR en cada centro es recomendable para su uso protocolizado

BACKGROUND: Speed of administration conditions the effectiveness of intravenous fibrinolysis in treating acute ischaemic stroke. To reduce the risk of haemorrhagic complications, the intervention is contraindicated in certain cases, such as where the International Normalised Ratio (INR) is ≥ 1.7. This study aimed to determine the reliability of point-of-care INR readings (POC-INR) taken using the CoaguChek ® XS portable coagulometer compared to laboratory results (L-INR). METHODS: We conducted a retrospective observational study of consecutive patients admitted to our centre with acute ischaemic stroke and who were treated with intravenous fibrinolysis, over a period of 4 years. Patients' INR was measured with a portable coagulometer and in the laboratory. Results were compared using the paired-sample t test; using L-INR results as a reference value, ROC analysis was performed to determine POC-INR with greater predictive value. RESULTS: The study included 210 patients with a mean age of 74.3 ± 11.5 years old; 18 (8.6%) were taking vitamin K antagonist oral anticoagulants (OAC). There were no significant differences between the 2 INR measurements in the population as a whole (POC-INR-L-INR difference: 0.001 ± 0.085; P=.82). In subgroup analysis, the results coincided for patients taking OACs (0.001 ± 0.081; P=.42) and those with L-INR ≤ 1.2 (0.008 ± 0.081; P=.16). For L-INR>1.2, however, the portable coagulometer underestimated INR (0.058±0.095; P=.01). Through ROC analysis, POC-INR < 1.6 was found to be the cut-off point with greatest sensitivity (100%) and specificity (98.97%) for identifying patients eligible for intravenous fibrinolysis (L-INR < 1.7). CONCLUSIONS: POC-INR shows a good correlation with L-INR. Our results suggest that the best threshold to predict an L-INR < 1.7 is POC-INR < 1.6. Internal validation studies for POC-INR should be considered in all treatment centres

Reliability of point-of-care coagulometer measurements in patients with acute ischaemic stroke receiving intravenous fibrinolysis. / Fiabilidad del coagulómetro portátil en pacientes con ictus isquémico agudo tratados con fibrinólisis intravenosa.

BACKGROUND: Speed of administration conditions the effectiveness of intravenous fibrinolysis in treating acute ischaemic stroke. To reduce the risk of haemorrhagic complications, the intervention is contraindicated in certain cases, such as where the International Normalised Ratio (INR) is ≥ 1.7. This study aimed to determine the reliability of point-of-care INR readings (POC-INR) taken using the CoaguChek® XS portable coagulometer compared to laboratory results (L-INR). METHODS: We conducted a retrospective observational study of consecutive patients admitted to our centre with acute ischaemic stroke and who were treated with intravenous fibrinolysis, over a period of 4 years. Patients' INR was measured with a portable coagulometer and in the laboratory. Results were compared using the paired-sample t test; using L-INR results as a reference value, ROC analysis was performed to determine POC-INR with greater predictive value. RESULTS: The study included 210 patients with a mean age of 74.3±11.5 years old; 18 (8.6%) were taking vitamin K antagonist oral anticoagulants (OAC). There were no significant differences between the 2 INR measurements in the population as a whole (POC-INR-L-INR difference: 0.001±0.085; P=.82). In subgroup analysis, the results coincided for patients taking OACs (0.001±0.081; P=.42) and those with L-INR ≤ 1.2 (0.008±0.081; P=.16). For L-INR>1.2, however, the portable coagulometer underestimated INR (0.058±0.095; P=.01). Through ROC analysis, POC-INR < 1.6 was found to be the cut-off point with greatest sensitivity (100%) and specificity (98.97%) for identifying patients eligible for intravenous fibrinolysis (L-INR < 1.7). CONCLUSIONS: POC-INR shows a good correlation with L-INR. Our results suggest that the best threshold to predict an L-INR < 1.7 is POC-INR < 1.6. Internal validation studies for POC-INR should be considered in all treatment centres.

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.

Performance of the LumiraDx Platform INR Test in an Anticoagulation Clinic Point-of-Care Setting Compared With an Established Laboratory Reference Method.

Vitamin K antagonists, such as warfarin, have a narrow therapeutic window; patients on these therapies therefore require regular international normalized ratio (INR) monitoring to maintain optimal dosing. This involves periodic checks and laboratory testing using venepuncture, which are often perceived as a burden. This study aimed to determine the accuracy and precision of the LumiraDx INR Test, a new point-of-care in vitro diagnostic platform, in an anticoagulation clinic setting. In this observational, cross-sectional study, precision of the LumiraDx INR Test was assessed using paired replicate samples (n = 366) and 3 test strip lots. Accuracy was determined by comparing capillary blood INR, ascertained by the LumiraDx INR Test, with venous plasma INR, measured by the laboratory reference instrument, the IL ACL ELITE Pro. Furthermore, INR was assessed across a range of hematocrit (25%-55%). In addition, feedback was collected from health-care professionals via a self-completed questionnaire. This trial was registered at ClinicalTrials.gov (NCT03682419). The precision (% coefficient of variation) of the LumiraDx INR Test was <4 when samples were applied by direct application or via a capillary transfer pipette, as well as between test strip lots. Accuracy of the LumiraDx INR Test, across the INR range of 0.8 to 7.5, was confirmed by a strong correlation of 0.965 (95% confidence interval: 0.959-0.970) when compared with the IL ACL ELITE Pro, which was maintained across the hematocrit range. Feedback from health-care professionals indicated that the instructions given by the system were easy to follow. In conclusion, the strong agreement between the LumiraDx Platform INR point-of-care test and the IL ACL ELITE Pro laboratory reference system, as well as between the different application methods and test lots, indicates that it can provide a rapid, accurate, and reliable INR analysis.

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.

[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.

Benefits and Pitfalls of Point-of-Care Coagulation Testing for Anticoagulation Management: An ACLPS Critical Review.

Objectives: Point-of-care (POC) testing is generally less precise and has higher reagent costs per test than laboratory-based assays. However, POC hemostasis testing can offer significant advantages in particular situations: patient-managed warfarin therapy as well as rapid turnaround time heparin management for intraoperative patients. Of note, POC hemostasis testing is generally approved for the purposes of anticoagulation monitoring and is inferior to laboratory coagulation testing for the diagnosis of congenital or acquired coagulopathy. Methods: The frequently used POC coagulation instruments for POC international normalized ratio and activated clotting time are reviewed, as well as their typical performance relative to central laboratory testing (where available). Results: Several cases are discussed that highlight the benefits, as well as pitfalls, of POC coagulation testing. Conclusions: POC coagulation testing for anticoagulation monitoring offers advantages in particular situations. Clear policies and protocols must be developed to guide proper use of POC versus central laboratory hemostasis testing.

Thrombolysis in stroke patients: Comparability of point-of-care versus central laboratory international normalized ratio.

BACKGROUND: In acute stroke patients, thrombolysis is one gold standard therapy option within the first four hours after the ischemic event. A contraindication for thrombolysis is an International Normalized Ratio (INR) value >1.7. Since time is brain, rapid and reliable INR results are fundamental. Aim was to compare INR values determined by central laboratory (CL) analyzer and Point-of-Care Testing(POCT)-device and to evaluate the quality of POCT performance in cases of potential therapeutic thrombolysis at a certified stroke unit. METHODS: In 153 patients INR measurements using POCT-devices (HEMOCHRON Signature Elite®) were compared to INR measurements (BCS®XP) performed at the central laboratory. Outlier evaluation was performed regarding the critical thrombolysis cut-off. RESULTS: Overall, we demonstrated a significant correlation (r = 0.809, p<0.0001) between both measurement methods. Mean value of the absolute difference between CL-INR and POCT-INR measurements was 0.23. In 95.4% of these cases, no differences regarding the critical cut-off (INR 1.7) were observed. POCT-INR values tended to be higher than the CL-INR values (p = 0.01). In 4.6% cases, a different value regarding thrombolysis cut-off was found. All patients were >75 years. CONCLUSIONS: POCT-INR measurements based on our POCT concept are suitable to determine INR values in critical stroke patients. Nevertheless, outlier evaluation is mandatory.

An evaluation of a coagulation system (Xprecia Stride) for utilisation in anticoagulation management.

AIM: To evaluate the reliability and performance of the Xprecia Stride coagulometer under the conditions in which it is most likely to be used. METHODS: The performance of the Xprecia Stride coagulometer was compared with a local laboratory and the CoaguChek systems routinely used for international normalised ratio (INR) estimation within one primary and one secondary care based anticoagulation clinic in Birmingham. Anticoagulation clinic personnel were trained to use the Xprecia Stride. Patients attending the clinics were eligible if aged ≥18 years and had received warfarin for at least 3 months. Consenting participants provided capillary blood samples for parallel testing on the Xprecia Stride and CoaguChek systems. At the secondary care clinic, a venous blood sample was also collected for laboratory INR estimation. INR results were compared using linear regression analysis and Bland-Altman plots. RESULTS: A total of 102 laboratory and 205 parallel coagulometer INR tests were performed. Linear regression revealed strong correlation between the Xprecia Stride and the laboratory (r=0.83) and between the Xprecia Stride and CoaguChek systems (r=0.92). Within the therapeutic range, agreement between the systems was very good with 87% of the Xprecia Stride and laboratory INR results and 93% of the Xprecia Stride and CoaguChek INR results being within 0.5 INR units of each other. CONCLUSION: INRs tested using the Xprecia Stride system showed good agreement with the laboratory and CoaguChek systems. Findings indicate that in the hands of the intended users the Xprecia Stride is accurate, reliable and acceptable for use in a routine clinical setting.

Performance evaluation of the microINR® point-of-care INR-testing system.

INTRODUCTION: Point-of-care International Normalised Ratio (INR) testing is used frequently. We evaluated the microINR® POC system for accuracy, precision and measurement repeatability, and investigated instrument and test chip variability and error rates. METHODS: Venous blood INRs of 210 patients on warfarin were obtained with Thromborel® S on the Sysmex CS-2100i® analyser and compared with capillary blood microINR® values. Precision was assessed using control materials. Measurement repeatability was calculated on 51 duplicate finger-prick INRs. Triplicate finger-prick INRs using three different instruments (30 patients) and three different test chip lots (29 patients) were used to evaluate instrument and test chip variability. RESULTS: Linear regression analysis of microINR® and Sysmex CS2100i® values showed a correlation coefficient of 0.96 (P < .0001) and a positive proportional bias of 4.4%. Dosage concordance was 93.8% and clinical agreement 95.7%. All acceptance criteria based on ISO standard 17593:2007 system accuracy requirements were met. Control material coefficients of variation (CV) varied from 6.2% to 16.7%. The capillary blood measurement repeatability CV was 7.5%. No significant instrument (P = .93) or test chip (P = .81) variability was found, and the error rate was low (2.8%). CONCLUSION: The microINR® instrument is accurate and precise for monitoring warfarin therapy.

Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor.

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

Performance of point-of-care international normalized ratio measurement to diagnose trauma-induced coagulopathy.

BACKGROUND: Trauma-induced coagulopathy (TIC) is a common feature after severe trauma. Detection of TIC is based upon classic coagulation tests including international normalized ratio (INR) value. Point-of-care (POC) devices have been developed to rapidly measure INR at the bedside on whole blood. The aim of the study was to test the precision of the Coagucheck® XS Pro device for INR measurement at hospital admission after severe trauma. METHODS: We conducted a prospective observational study in a French level I trauma center. From January 2015 to May 2016, 98 patients with a suspicion of a post-traumatic acute hemorrhage had POC-INR measurement on whole blood concomitantly to classic laboratory INR determination (lab-INR) on plasma at hospital admission. The agreement between the two methods in sorting three predefined categories of INR (normal coagulation, moderate TIC and severe TIC) was evaluated using the Cohen's kappa test with a quadratic weighting. The correlation between POC-INR and lab-INR was measured using the Pearson's coefficient. We also performed a Bland and Altman analysis. RESULTS: The agreement between the lab-INR and the POC-INR was moderate (Kappa = 0.45 [95% CI 0.36-0.50]) and the correlation between the two measurements was also weak (Pearson's coefficient = 0.44 [95% CI 0.27-0.59]). Using a Bland and Altman analysis, the mean difference (bias) for INR was 0.22 [95% CI 0.02-0.42], and the standard deviation (precision) of the difference was 1.01. DISCUSSION/CONCLUSION: POC Coagucheck® XS Pro device is not reliable to measure bedside INR. Its moderate agreement with lab-INR weakens the usefulness of such device after severe trauma. TRIAL REGISTRATION: NCT02869737 . Registered 9 August 2016.

The microINR portable coagulometer: analytical quality and user-friendliness of a PT (INR) point-of-care instrument.

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.