Point-of-care testing of the international normalized ratio in patients with antiphospholipid antibodies

2005 ◽  
Vol 94 (12) ◽  
pp. 1196-1202 ◽  
Author(s):  
Gregory P. Samsa ◽  
Thomas L. Ortel ◽  
Stephanie L. Perry
Keyword(s):  
Atrial Fibrillation ◽  
Whole Blood ◽  
Antiphospholipid Antibodies ◽  
Point Of Care ◽  
International Normalized Ratio ◽  
Absolute Difference ◽  
Factor X ◽  
Point Of Care Testing ◽  
Laboratory Plasma ◽  
Finger Stick

SummaryAntiphospholipid antibodies can influence the results of clotting tests in a subset of patients, which can be a major obstacle in monitoring warfarin. The aim was to determine if point-of-care testing of the International Normalized Ratio (INR) is influenced by antiphospholipid antibodies. We compared 59 patients receiving warfarin for a diagnosis of antiphosphoipid antibody syndrome (APS) to 49 patients receiving warfarin for atrial fibrillation to evaluate the consistency between INR results obtained by different methods. INR results obtained by finger stick (capillary whole-blood) and venipuncture (non-citrated and citrated whole-blood) were compared with our laboratory plasma-based prothrombin time assay. Five patients (8%) with APS and both elevated anti-β2glycoprotein I levels and positive lupus anticoagulants had non-measurable ProTime® INR results and generally higher Hemochron® Signature INR results than the plasma-based method, but the corresponding chromogenic factor X results were not supratherapeutic. For the remaining patients, differences between the plasma-based INR and the point-of-care INR results ranged from 0.2±0.2 to 0.4±0.3. The differences were similar for patients with APS and atrial fibrillation for all INR comparisons with the exception of the plasma-based method compared with the ProTime, which showed a mean absolute difference of 0.4±0.3 for APS patients and of 0.2±0.2 for atrial fibrillation patients (p=0.02). In a subset ofAPS patients, the ProTime® system will not yield an INR result and the HEMochron Signature (citrate and non-citrate whole-blood) INR results will exhibit elevated INR results. For this subset of APS patients, we suggest using an alternative method to monitor warfarin.

Point of Care Monitoring of the International Normalized Ratio in Patients with Antiphospholipid Antibodies.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1855-1855 ◽  
Author(s):  
Stephanie L. Perry ◽  
Gregory P. Samsa ◽  
Thomas L. Ortel
Keyword(s):  
Whole Blood ◽  
Antiphospholipid Antibodies ◽  
Point Of Care ◽  
Method Comparison ◽  
Correlation Coefficients ◽  
International Normalized Ratio ◽  
Absolute Difference ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Antibody Levels

Abstract Warfarin is effective in decreasing recurrent thrombosis in patients with antiphospholipid antibody syndrome (APS). Antiphospholipid antibodies (APAs) can influence the results of clotting tests in a subset of these patients, which can be a major obstacle in monitoring warfarin. In this study, 59 patients receiving warfarin for a diagnosis of APS were compared to 49 patients receiving warfarin for atrial fibrillation (AF) with regard to consistency between International Normalized Ratio (INR) results obtained from two Point of Care (POC) monitors and a standard plasma-based method used in the coagulation laboratory. INR results were obtained using a fingerstick for whole blood on the ProTime® monitor (International Technidyne Corp, ITC, Edison, NJ) and by venipuncture using both citrated and non-citrated whole-blood on a HEMOCHRON®Signature (Hr. Sig.) monitor (ITC). Parallel INR measurements were obtained on an MDA-180 analyzer (bioMeriéux, Durham, NC), using Simplastin-HTF. Additional tests included chromogenic factor Xa (CFXa) and tests for APAs (antiphospholipid, anti-β2-glycoprotein I [β2GPI], and antiprothrombin ELISA’s). Insufficient blood was obtained from 5 patients for testing with the ProTime® (3 AF, 2 APS). For an additional 5 patients, all with APS, sufficient blood was obtained, but an INR could not be determined by the instrument (8%). Single INR results on the ProTime® were obtained from 2 of these patients on repeat testing. The data were analyzed with the 100 patients who had at least one INR result with the ProTime®. Analyses included determination of the means of absolute differences between each method of obtaining INR results, correlations between INR results and CFXa results, and correlations with APAs results. Systematic differences were found for each INR method comparison, ranging from 0.24±0.23 to 0.41±0.29, with correlation coefficients ranging from 0.54 to 0.80. The differences were similar for AF and APS patients for all INR comparisons with the exception of the results comparing the standard plasma-based method with the ProTime®, which showed a mean absolute difference of 0.24 for AF patients and 0.39 for APS patients (p=0.01). Preliminary data analysis did not show perfect calibration between the CFXa and the different methods for obtaining INR results for either patient group. Correlation coefficients ranged from 0.3 to 0.7 when comparing CFXa to each INR method, and the best correlation was between the standard plasma INR and the CFXa for patients with AF (0.65). Review of testing for APAs at the time of INR testing revealed that 10 patients with AF had elevated antibody levels (20%; all by antiphospholipid ELISA only and most only minimally elevated), compared to 27 patients with APAs (45%, with 21 having elevated anti-β2 GPI antibody levels). The five patients with non-measurable ProTime® INRs had elevated anti-β2GPI levels and generally higher INRs with the Hr. Sig., but CFXa results were not supratherapeutic. In conclusion, these results suggest that in a subset of patients with APAs, the ProTime® will not yield any results and can not be used due to the internal QC set of the monitor. APA testing did not specifically identify which APS patients would most likely have problems with INR testing.

European Concerted Action on Anticoagulation (ECAA): International Normalized Ratio Variability of CoaguChek and TAS Point-of-Care Testing Whole Blood Prothrombin Time Monitors

2002 ◽  
Vol 88 (12) ◽  
pp. 992-995 ◽  
Author(s):  
M. Keown ◽  
N. Chauhan ◽  
C. Shiach ◽  
A. M. H. P. van den Besselaar ◽  
A. Tripodi ◽  
...  
Keyword(s):  
Prothrombin Time ◽  
Whole Blood ◽  
Point Of Care ◽  
International Normalized Ratio ◽  
Operator Technique ◽  
Concerted Action ◽  
Point Of Care Testing ◽  
Blood Samples ◽  
International Normalised Ratio ◽  
Whole Blood Samples

SummaryThe object was to assess the variability in displayed International Normalised Ratio (INR) between monitors of the same manufacture using whole blood samples from the same subjects. Two brands of monitor, CoaguChek Mini and the TAS PT-NC were tested.14 instruments of each brand were tested on the same day at the same laboratory by the same operator using identical blood samples to avoid between-centre differences in samples and operator technique. Whole blood samples from two normal donors and four coumarintreated patients were tested to assess between-instrument variability of INR.Results have been coded. There was a much wider dispersion of INR on Brand B than on Brand A. One Brand A instrument failed to give a result with one of the two whole blood samples from one patient. One Brand B monitor gave an aberrant result with one of the samples from a normal subject.On both brands of monitor, INR variability appeared to be due mainly to duplication differences rather than between-instrument variability on both normal and coumarin whole blood samples.

scholarly journals RAMPTM: A Rapid, Quantitative Whole Blood Immunochromatographic Platform for Point-of-Care Testing

1999 ◽  
Vol 45 (9) ◽  
pp. 1676-1678 ◽  
Author(s):  
Donald E Brooks ◽  
Dana V Devine ◽  
Paul C Harris ◽  
Joanne E Harris ◽  
Mark E Miller ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Point Of Care Testing

Thromboelastometry as an Alternative Method for Coagulation Assessment in Pediatric Patients Undergoing Invasive Procedures: A Pilot Study

2018 ◽  
Vol 29 (03) ◽  
pp. 298-301
Author(s):  
Miroslav Durila ◽  
Jakub Jonas ◽  
Marianna Durilova ◽  
Michal Rygl ◽  
Jiri Skrivan ◽  
...  
Keyword(s):  
Whole Blood ◽  
Pediatric Patients ◽  
Point Of Care ◽  
Venous Catheter ◽  
International Normalized Ratio ◽  
Fresh Frozen Plasma ◽  
Severe Bleeding ◽  
Invasive Procedures ◽  
Coagulation Profile ◽  
Alternative Method

Introduction Standard coagulation tests (activated partial thromboplastin time [aPTT] and prothrombin time [PT]) are used for the assessment of coagulation profile in critically ill pediatric patients undergoing invasive interventions such as insertion of central venous catheter, tonsillectomy, laparotomy, etc. However, these tests do not reflect the profile of whole blood coagulation. Rotational thromboelastometry (ROTEM) as a point of care (POC) viscoelastic test may serve as an alternative method. Due to its ability to assess coagulation profile of the whole blood, it might yield normal results despite prolonged aPTT/PT results. The aim of this study was to find out if there was any severe bleeding during or after invasive procedures if ROTEM test was normal despite prolonged values of aPTT/PT in pediatric patients. Materials and Methods We retrospectively analyzed data for the years 2015 to 2017 for pediatric patients with prolonged values of aPTT or PT and normal ROTEM tests—internal thromboelastometry (INTEM) (assessing internal pathway of coagulation) and external thromboelastometry (EXTEM) (assessing external pathway of coagulation)—and we looked for severe bleeding during or after invasive procedures. Results In 26 pediatric patients (children from 2 months to 17 years old), we found that INTEM and EXTEM tests showed normal coagulation despite prolonged values of aPTT ratio with a median of 1.47 (minimum 1.04 and maximum 2.05), international normalized ratio with a median of 1.4 (minimum 0.99 and maximum 2.10), and PT ratio with a median of 1.30 (minimum 0.89 and maximum 2.11). In these patients, no severe bleeding was observed during interventions or postoperatively. Conclusion Our data support using thromboelastometry method as an alternative coagulation test for the assessment of coagulation profile in pediatric patients undergoing surgical or other invasive procedures, especially using it as a POC test. All invasive procedures in our study were performed without severe bleeding despite prolonged values of PT/aPTT with normal ROTEM results. It seems that ROTEM assessment of coagulation may lead to decreased administration of fresh frozen plasma and shorten time of patient preparation for intervention.

International Normalized Ratio (INR) Determined by Plasma-Based Methods Versus Point-of-Care Instruments in Patients with Antiphospholipid Antibody Syndrome.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1067-1067 ◽  
Author(s):  
Stephan Moll ◽  
Lauren McKnight ◽  
Allison Deal
Keyword(s):  
Point Of Care ◽  
Clinical Decision ◽  
Analysis Data ◽  
International Normalized Ratio ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Factor X ◽  
Research Support ◽  
Glycoprotein I ◽  
Factor Ii

Abstract Abstract 1067 Poster Board I-89 Background: In some patients with antiphospholipid antibody (APLA) syndrome treated with warfarin, the International Normalized Ratios (INRs) obtained from plasma, as well as from full blood via fingerstick by older point-of-care (POC) devices, are unreliable. Reliability of newer POC devices in APLA syndrome patients is unknown and was investigated in the present study. Methods: 60 patients on stable warfarin were enrolled: 30 with APLA syndrome, 30 without. INRs were determined using 4 POCs: CoaguChekXS®, ProTime®, the investigational ProTime®, and INRatio2®. Plasma from phlebotomy was tested for: PT, factor II activity, chromogenic factor X, anticardiolipin and anti-beta-2-glycoprotein I antibodies, lupus anticoagulant. Analysis: Data from the venipuncture INRs from the patients without APLA are used to estimate the relationship between INR and Factor II level and determine the therapeutic range of Factor II. Using the same therapeutic INR range, for each individual POC test the proportion of patients whose clinical decision based on the POC instrument is correct is estimated, along with 95% confidence intervals. This is done for patients with and without APLA. These two proportions are compared between the two groups using Fisher's Exact Tests; nominal p-values are reported. A similar analysis is done using the Factor X test as the gold standard. Results: Data collection has been completed; analysis of results is pending and will be available before December 2009. Conclusions: Data analysis will show whether the presently available POC devices give reliable INR results in patients with APLA syndrome on warfarin and can be reliably used to monitor warfarin therapy. Disclosures: Moll: Hemosense: research support; Roche: reserarch support; ITC: Consultancy, research support. McKnight:ITC: Honoraria. Deal:ITC: Consultancy.

scholarly journals P295 Comparative Assessment of Infliximab Trough Levels between Point-of-Care Testing and current Standard of Care (enzyme linked immunosorbent assay) in patients with Inflammatory Bowel Disease

2021 ◽  
Vol 15 (Supplement_1) ◽  
pp. S325-S325
Author(s):  
D Maniero ◽  
G Lorenzon ◽  
I Marsilio ◽  
A Rigo ◽  
R Cardin ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Whole Blood ◽  
Point Of Care ◽  
Enzyme Linked Immunosorbent Assay ◽  
Blood Collection ◽  
Point Of Care Testing ◽  
Deming Regression ◽  
Inflammatory Bowel ◽  
Trough Levels

Abstract Background Infliximab (IFX) is a monoclonal antibody that targets cytokine tumor necrosis factor; it is used for the treatment of patients with active inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC). IFX induces and maintains remission and mucosal healing in patients with IBD. Measurement of trough levels (TL) of IFX is important to assess if the drug is within its therapeutic concentrationand to explain lack/loss of response. Standard laboratory tests to assess IFX trough levels (enzyme linked immunosorbent assays, ELISA) present some downsides, related to the long turnaround (about 3 hours), and the need of specialized equipment and laboratory personnel. For this reason, point-of care testing (POCT) was developed to provide results within a few minutes from blood collection, leading to a decision-making approach. Aim To determine the degree of analytical correlation between a recently developed POCT (ProciseDx) IFX assay which analyze capillary whole blood and the comparative ELISA from serum. Methods From October 2020 to January 2021, patients (aged≥18 years) taking IFX were recruited at Gastroenterology Unit, Padua University Hospital. In each patient, IFX levels from capillary whole blood collected by finger stick were performed using the ProciseDx IFX assay with reportable range between 1.7-77.2 µg/mL; at the same time, a serum sample from venous blood was collected to carry out Grifols’ Promonitor ELISA test (range 0.035–14.4 µg/mL). A Deming regression test was used to identify the correlation between the two methods. Results Eighty-seven patients were enrolled (63% males; mean age of 44±16), with 52% of them having CD, 45% UC and 3% an undetermined-Inflammatory Bowel Disease. The assessment with ProciseDx POCT was feasible in each patient and only in three cases blood collection from finger prick was repeated. Moreover, from blood collection to results we needed about 3±0.5 minutes, while serum ELISA analysis required the collection of at least 40 samples (around three weeks at our centre) and 3 hours to be performed. 39 patients (59% males; mean age of 44±16) had TL as assessed by ProciseDx IFX assay lower than 1.7 or greater than 14.4 µg/mL, in accordance with ELISA assessment. Among the remaining 48 patients (67% males with mean age of 45±17), The correlation between the two tests was high (the total results showed an R squared of 0.691 (95% CI 0.717-0.902). Conclusion The ProciseDx POCT has good accuracy but was more rapid and easy to be performed in providing the results of Therapeutic Drug Monitoring in outpatients taking IFX. This could lead to a more effective optimization of the biological drug, thus avoiding treatment failure.

scholarly journals Point-of-care coagulation testing for reducing in-hospital delay in thrombolysis

2018 ◽  
Vol 26 (4) ◽  
pp. 218-224 ◽  
Author(s):  
Jung Hee Han ◽  
Seongsoo Jang ◽  
Mi-Ok Choi ◽  
Mi-Jeong Yoon ◽  
Seung-Bok Lim ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Prothrombin Time ◽  
Laboratory Testing ◽  
Point Of Care ◽  
Intravenous Thrombolysis ◽  
International Normalized Ratio ◽  
Interquartile Range ◽  
Time Interval ◽  
Central Laboratory ◽  
Point Of Care Testing

Background: The confirmation of prothrombin time international normalized ratio by a central laboratory often delays intravenous thrombolysis in patients with acute ischemic stroke. Objectives: We investigated the feasibility, reliability, and usefulness of point-of-care determination of prothrombin time international normalized ratio for stroke thrombolysis. Methods: Among 312 patients with ischemic stroke, 202 who arrived at the emergency room within 4.5 h of stroke onset were enrolled in the study. Patients with lost orders for point-of-care testing for the prothrombin time international normalized ratio or central laboratory testing for the prothrombin time international normalized ratio (n = 47) were excluded. We compared international normalized ratio values and the time interval from arrival to the report of test results (door-to-international normalized ratio time) between point-of-care testing for the prothrombin time international normalized ratio and central laboratory testing for the prothrombin time international normalized ratio. In patients who underwent thrombolysis, we compared the time interval from arrival to thrombolysis (door-to-needle time) between the current study population and historic cohort at our center. Results: In the 155 patients included in the study, the median door-to-international normalized ratio time was 9.0 min (interquartile range, 5.0–12.0 min) for point-of-care testing for the prothrombin time international normalized ratio and 46.0 min (interquartile range, 38.0–55.0 min) for central laboratory testing for the prothrombin time international normalized ratio (p < 0.001). The intraclass correlation coefficient between point-of-care testing for the prothrombin time international normalized ratio and central laboratory testing for the prothrombin time international normalized ratio was 0.975 (95% confidence interval: 0.966–0.982). Forty-nine of the 155 patients underwent intravenous thrombolysis. The door-to-needle time was significantly decreased after implementation of point-of-care testing for the prothrombin time international normalized ratio (median, 23.0 min; interquartile range, 16.0–29.8 vs median, 46.0 min; interquartile range, 33.5–50.5 min). Conclusion: Utilization of point-of-care testing for the prothrombin time international normalized ratio was feasible in the management of patients with acute ischemic stroke. Point-of-care testing for the prothrombin time international normalized ratio was quick and reliable and had a pivotal role in expediting thrombolysis.

A plasma separator with a multifunctional deformable chamber equipped with a porous membrane for point-of-care diagnostics

The Analyst ◽  
2020 ◽  
Vol 145 (18) ◽  
pp. 6138-6147
Author(s):  
Xianbo Qiu ◽  
Huiqin Jiang ◽  
Xiaolei Zhang ◽  
Ke Li ◽  
Shengxiang Ge ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Porous Membrane ◽  
Point Of Care Testing ◽  
Plasma Separation ◽  
Point Of Care Diagnostics ◽  
Short Time

For point-of-care testing, a membrane-assisted, sedimentation-facilitated plasma separator with a multifunctional deformable chamber is developed to perform plasma separation from undiluted whole blood in a short time.

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