Abstract Number: PB0449
Meeting: ISTH 2020 Congress
Theme: Diagnostics and OMICs » Biomarkers of Thrombosis and Hemostasis
Background: The LumiraDx INR Test is a new point of care in vitro diagnostic system for the quantitative determination of Prothrombin Time expressed as International Normalised Ratio (INR) at the point of care (POC). Within Europe, there are country to country differences in preferential vitamin K antagonist (VKA) prescription. In Germany and surrounding countries, Phenprocoumon is the most commonly prescribed. Agreement between the LumiraDx INR test and the IL ACL Elite Pro has been demonstrated previously in patients taking Coumadin.
Aims: The aim of this study was to evaluate the INR results in a German clinical setting with patients taking Phenprocoumon using the LumiraDx INR, and comparing the results to the laboratory reference methods, the ACL Elite Pro and Sysmex CS5100.
Methods: This study was an observational, cross-sectional study with 102 subjects (24 female and 78 male) taking Phenprocoumon. Ages ranged from 36 – 88 years. Devices used were CE marked for INR measurement, conducted by healthcare professionals. In part 1 (25 subjects), samples of venous whole blood were analysed on the LumiraDx instrument and compared to venous plasma INR determined by both reference methods. In part 2 (77 subjects) a comparison of capillary whole blood INR (direct fingerstick application) determined by LumiraDx INR Test was made to venous plasma INR determined by the laboratory reference methods.
Results: The LumiraDx INR Results were plotted against the reference methods in part 1 and 2 and showed strong agreement across the range 1.3-5.2 INR.
| Sample | Reference Method | Slope | Slope CI | Intercept | Intercept CI | r |
| Plasma part 1 | ACL Elite Pro | 1.055 | [0.937,1.161] | -0.156 | [-0.375,0.184] | 0,981 |
| Plasma part 1 | Sysmex CS5100 | 1.038 | [0.917,1.136] | -0.104 | [-0.300,0.225] | 0.982 |
| Plasma part 2 | ACL Elite Pro | 1.002 | [0.945,1.073] | -0.029 | [-0.173,0.108] | 0.959 |
| Plasma part 2 | Sysmex CS5100 | 1.000 | [0.923,1.000] | -0.050 | [-0.093,0.142] | 0.975 |
| Capillary Blood Part 2 | ACL Elite Pro | 0.951 | [0.874,1.033] | -0.028 | [-0.248,0.154] | 0.949 |
| Capillary Blood Part 2 | Sysmex CS5100 | 0.923 | [0.846, 1.000] | 0.015 | [-0.200, 0.186] | 0.950 |
[Summary of the Method Comparison Results of the LumiraDx INR Test]
Conclusions: Different VKA anticoagulation therapies, i.e. warfarin and phenprocoumon, do not influence the accuracy of the LumiraDx INR Test results. Overall, the LumiraDx INR Test can be used by healthcare professionals at the POC to provide reliable INR monitoring of patients who are receiving VKA therapy.
Funding: This study was sponsored by LumiraDx UK Ltd. Dumyat Business Park, Alloa. UK. 0920612
To cite this abstract in AMA style:
Voller H, Ellis J, Loecherbach J. Evaluation of the Accuracy of INR Values Measured by a POCT System in a German Clinic with Patients Taking Phenprocoumon as VKA Therapy [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/evaluation-of-the-accuracy-of-inr-values-measured-by-a-poct-system-in-a-german-clinic-with-patients-taking-phenprocoumon-as-vka-therapy/. Accessed October 1, 2023.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/evaluation-of-the-accuracy-of-inr-values-measured-by-a-poct-system-in-a-german-clinic-with-patients-taking-phenprocoumon-as-vka-therapy/