Key result
Abbott PT INR cartridges show pronounced positive bias at INR >4.0, significantly reduced by PT Plus.
Why the study?
POC INR testing is susceptible to systematic bias, particularly at supratherapeutic levels, which can lead to inappropriate warfarin adjustments and increased thrombotic risk.
Do Abbott POC INR devices exhibit systematic bias compared to Roche devices and laboratory testing?
Observational
Do Abbott POC INR devices exhibit systematic bias compared to Roche devices and laboratory testing?
Significant systematic bias in Abbott POC INR devices at supratherapeutic levels underscores the necessity of confirmatory venous testing when POC INR exceeds critical thresholds.
Answers are grounded in this paper and cite their sources.
Abbott POC INR positive bias shift at high values risks overcorrection; supports device-specific QA surveillance and lab confirmation before warfarin adjustments.
OBJECTIVES: Point-of-care (POC) International Normalised Ratio (INR) testing provides rapid anticoagulation monitoring. Still, it is susceptible to systematic bias, particularly at supratherapeutic levels, which can lead to inappropriate warfarin dose adjustments and increased thrombotic risk. This study evaluated bias trends between Abbott and Roche POC INR devices. METHODS: Bias trends were assessed using Royal College of Pathologists of Australasia Quality Assurance Programs survey data (2023-2025), in-house verification, and patient sample comparisons against laboratory instrument testing used as a comparative reference mark (Werfen ACL TOP). RESULTS: Abbott PT INR cartridges demonstrated a shift from negative bias in 2023 to pronounced positive bias in 2024, with discrepancies most evident at INR >4.0. The introduction of Abbott PT Plus cartridges in 2025 significantly reduced bias, achieving near alignment with Roche CoaguChek Pro II and laboratory methods tested in this study. Comparative reagent analysis highlighted the influence of thromboplastin source and ISI values on harmonisation. CONCLUSIONS: Findings reinforce the need for confirmatory venous testing when POC INR exceeds critical thresholds, and emphasise the importance of ongoing performance monitoring, structured escalation policies, and transparent communication with manufacturers.
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Arunachalam et al. (2026) conducted an observational in Anticoagulation monitoring. Abbott POC INR devices vs. Roche POC INR devices and laboratory testing was evaluated on Bias trends in INR testing. Abbott PT INR cartridges showed pronounced positive bias at INR >4.0 in 2024 compared to Roche and laboratory methods, which was significantly reduced by Abbott PT Plus cartridges in 2025.
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