Accuracy of point of care coagulometers compared to reference laboratory measurements in patients on oral anticoagulation therapy

Jean-Guillaume Dillinger; Thiziri Si Moussi; Natacha Berge; Claire Bal Dit Sollier; Patrick Henry; Ludovic Drouet

doi:10.1016/j.thromres.2016.02.006

Accuracy of point of care coagulometers compared to reference laboratory measurements in patients on oral anticoagulation therapy

Thromb Res. 2016 Apr:140:66-72. doi: 10.1016/j.thromres.2016.02.006. Epub 2016 Feb 20.

Authors

Jean-Guillaume Dillinger¹, Thiziri Si Moussi², Natacha Berge³, Claire Bal Dit Sollier³, Patrick Henry², Ludovic Drouet³

Affiliations

¹ Department of Cardiology, Inserm U942, Lariboisiere Hospital, AP-HP, Paris Diderot University, Sorbonne Paris Cité, Paris, France; Thrombosis and Atherosclerosis Research Unit, Vessels and Blood Institute (IVS), Anticoagulation Clinic (CREATIF), Lariboisiere Hospital, Paris VII University, EA 7334 REMES, Paris, France. Electronic address: jean-guillaume.dillinger@aphp.fr.
² Department of Cardiology, Inserm U942, Lariboisiere Hospital, AP-HP, Paris Diderot University, Sorbonne Paris Cité, Paris, France.
³ Thrombosis and Atherosclerosis Research Unit, Vessels and Blood Institute (IVS), Anticoagulation Clinic (CREATIF), Lariboisiere Hospital, Paris VII University, EA 7334 REMES, Paris, France.

PMID: 26901852
DOI: 10.1016/j.thromres.2016.02.006

Abstract

Background: Vitamin K antagonists (VKA) are widely prescribed throughout the world. Patients on VKA therapy require international normalized ratio (INR) monitoring of venous blood to ensure the response remains within the therapeutic window. Point-of-care devices (POC-INR) can safely and easily monitor VKA efficacy but need to be evaluated in practice. The aim of this study was to assess the precision and accuracy of a new POC-INR (Qlab) compared to the laboratory plasma technique and the CoaguChek-XS system.

Methods: Consecutive patients on VKA referred to our institution were included. The study was designed to analyze 75 patients divided equally in the following subgroups: INR<2; INR=2-3; INR>3. INR was measured with an established laboratory method (INRREF) with an international sensitivity index of 1.0 and by two different POC-INRs: the Qlab (INRQlab) and the CoaguChek-XS systems (INRXS).

Results: 82 patients treated mainly for atrial fibrillation or venous thromboembolism disease were included. Precision in therapeutic range (INR=2-3) of both POC-INRs was satisfactory with a coefficient of variation of 4.6% for the Qlab and 4.3% for the CoaguChek-XS. INRRef was 2.70 ± 1.36, INRQlab 2.59 ± 1.25 and INRXS 2.89 ± 1.37. Accuracy was low with the Qlab (R(2)=0.64) and higher with the CoaguChek-XS (R(2)=0.94). The mean relative difference from the INRRef was higher for the Qlab (18.4%) than for the CoaguChek-XS (12.9%). Clinical concordance was lower with the Qlab (78.2%) than with the CoaguChek-XS (90.0%).

Conclusion: This study suggests that the Qlab has accuracy limitations with clinical consequences. New POC-INR devices require careful evaluation prior to clinical implementation.

Keywords: International normalized ratio; Oral anticoagulant; Point-of-care testing; Prothrombin time; Vitamin K antagonist.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Administration, Oral
Adult
Aged
Anticoagulants / administration & dosage
Anticoagulants / therapeutic use*
Atrial Fibrillation / drug therapy*
Blood Coagulation / drug effects
Drug Monitoring
Female
Humans
International Normalized Ratio*
Male
Middle Aged
Point-of-Care Systems*
Prothrombin Time
Venous Thromboembolism / drug therapy*
Vitamin K / antagonists & inhibitors*

Substances

Anticoagulants
Vitamin K