Comparison of International Normalized Ratios provided by two point-of-care devices and laboratory-based venipuncture in a pharmacist-managed anticoagulation clinic

Donaldson, Mark; Sullivan, John; Norbeck, Amber

doi:10.2146/ajhp100096

Cited by 32 publications

(29 citation statements)

References 26 publications

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“…5 Williams et al published a study in 2007, based on 97 INR samples from patients in a pediatric age group, in which 13% of cases would have been treated differently if the Coaguchek XS device had been used and reported that 19% of the samples had variation greater than 0.5 INR points. The study also compared the device with its predecessor (Coaguchek S), observing that it offered greater efficacy and recommending substitution.6 food and medicines.…”

Section: Discussionmentioning

confidence: 99%

Comparison between the conventional method and a portable device for determination of INR

2014

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Context: Anticoagulation with warfarin is considered the appropriate treatment for venous thromboembolism and other thrombotic pathologies. Regular INR control is required for dosage adjustment and therapeutic control. Use of portable monitoring systems optimizes management of these patients. Objective: To compare INR measurements taken using the portable Coaguchek XS system in capillary blood with the standard laboratory method using venous blood. Method: Fifty-two samples each of venous and capillary blood were collected from nineteen patients on warfarin, who had been admitted to the Hospital da Beneficência Portuguesa de São Paulo, and analyzed using the conventional method and the Coaguchek XS system, respectively. Results: Spearman' s correlation coefficient (r) for the overall performance of the two methods was 0. 978 (p<0.0001; Exclusion criteria. samples were excluded if problems affected biological material collection.Determination of PT by the conventional method. 10 mL venous blood samples were collected into tubes containing 3.8% sodium citrate solution. Plasma was extracted from the samples by centrifugation at 3,800 rpm for 5±2 minutes and then the PT with INR was assayed using an ACL Elite Pro automated coagulation analyzer and a kit containing thromboplastin Recombiplastin 2G solution with an International Sensitivity Index (ISI) of 1.0.Determination of PT using the portable test. Samples of capillary blood were taken within one hour of collection of samples for the conventional method. Samples of approximately 10 µL were taken by finger stick from the finger pad of the first finger of patients' non-dominant hand, using Accu-Chek Safe-T-Pro Uno lancets. The blood drop was placed onto a Coaguchek XS PT test strip containing human recombinant thromboplastin with an ISI of 1.0 and the device displayed the result in approximately one minute.Classification of samples. The results for the 52 samples were classified by therapeutic range: INR < 2.0; INR 2.0 -3.5; or INR > 3.5.Ethical approval. The research project was approved by the Research Ethics Committee at the Hospital da Beneficência Portuguesa de São Paulo and all patients indicated their agreement to participation by signing consent forms. Statistical analysisThe INR results provided by the two different methods were analyzed for the entire sample and for the three subsets: INR <2.0; INR 2.0-3.5; and INR >3.5. The following analyses were performed: Student's t test for paired samples, Spearman's correlation index and the BlandAltman test, for evaluation of the differences between results. A 95% confidence interval and an α error of p<0.05 for statistical significance were adopted. Microsoft Excel 2007 was used for statistical analysis with the XLSTAT (trial version) and Analyze-it add-ins.

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Section: Discussionmentioning

confidence: 99%

Comparison between the conventional method and a portable device for determination of INR

2014

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“…27 Additional studies have demonstrated a wide range of differences between POC and standard results as well as variability among POC devices, which introduces concern regarding the reliability and reproducibility of POC results. 28,29 …”

Section: Discussionmentioning

confidence: 99%

All the bang without the bucks

Goodman

Makley

Hanseman

et al. 2015

Journal of Trauma and Acute Care Surgery

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BACKGROUND Rapid assessment and treatment of coagulopathy reduces postinjury morbidity and mortality. Although thrombelastography (TEG) may be more accurate and efficient than conventional coagulation tests, it requires significant financial and personnel investments. We hypothesized that point-of-care international normalized ratio (POC INR) may provide a rapid and accurate alternative to TEG. METHODS A retrospective review of sequential trauma patients who underwent both POC INR and rapid TEG (r-TEG) testing upon presentation to a Level I trauma center from July 2012 to December 2013 was performed. POC INR was compared with r-TEG values (R value, K time, α angle, maximum amplitude, percent clot lysis in 30 minutes) and transfusion requirements. Vital signs, admission laboratory values, and injury severity were analyzed. POC INR and venous blood gas testing was performed in the emergency department. All results and Pearson correlations noted were significant if p < 0.05. RESULTS We identified 628 trauma patients with concomitant r-TEG and POC INR testing. Median Injury Severity Score (ISS) was 13, 20% arrived in shock (base value < −5), 21% were transfused, and 11% died. POC INR correlated with all r-TEG values, with stronger correlations for patients in shock. POC INR and r-TEG had similar correlations with blood products transfused at 4 hours and 24 hours, but only POC INR predicted substantial bleeding and massive transfusion. POC INR also correlated strongly with standard INR testing. POC INR test duration was less than 1 minute, compared with at least 30 minutes for r-TEG. Total cohort charges for POC INR were estimated at $21,980 versus $396,896 for r-TEG. CONCLUSION POC INR testing is faster and cheaper than r-TEG. In addition, POC INR correlates not only with r-TEG values but also with acute blood product transfusions. POC INR provides a practical alternative for rapid coagulopathy assessment in the trauma patient at institutions that lack TEG capability. LEVEL OF EVIDENCE Diagnostic study, level III. Therapeutic/care management study, level IV.

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“…However, discrepancies between INRs determined by POC-instruments and laboratory measurements are reported (9,10,23) , and the discrepancies may have clinical impact (6,28) . It is therefore important that the causes of these differences are understood.…”

Section: Discussionmentioning

confidence: 99%

“…POC instruments are calibrated by the manufacturer and the precision and accuracy for some of the instruments have been examined (5 -7) . The performance of the newest POC instruments has improved (8) , although there are still challenges (9) , especially at the high end of the INR range (10) .…”

Section: Introductionmentioning

confidence: 99%

Effect of coagulation factors on discrepancies in International Normalized Ratio results between instruments

Sølvik

Røraas²,

Petersen³

et al. 2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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Comparison of International Normalized Ratios provided by two point-of-care devices and laboratory-based venipuncture in a pharmacist-managed anticoagulation clinic

Abstract: INR measurements generated by POC devices exhibited positive bias, compared with laboratory-based venipuncture, for INR values at the high end of the INR range.

Cited by 32 publications

References 26 publications

Comparison between the conventional method and a portable device for determination of INR

Comparison between the conventional method and a portable device for determination of INR

All the bang without the bucks

Effect of coagulation factors on discrepancies in International Normalized Ratio results between instruments

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