Development and validation of a point-of-care coagulation assay for rapid assessment of Warfarin therapy in resource-limited clinical settings

Project Abstract

The rising global burden of thromboembolic disease and the reliance on warfarin for long-term anticoagulation necessitate reliable, rapid, and accessible monitoring tools, particularly in resource-limited clinical settings where centralized laboratory services are often unavailable or delayed. This study reports the development and validation of a point-of-care coagulation assay designed to rapidly assess warfarin therapy by measuring the prothrombin time (PT) and international normalized ratio (INR) using a microfluidic cartridge and a portable reader, enabling timely dose adjustments at the bedside or in remote clinics. The assay integrates a stabilized thromboplastin reagent, minimal sample handling, and a robust optical or impedance-based readout that correlates with standard INR values obtained by certified reference laboratories. Methodologically, the project employed a multi-phase approach analytical validation to establish precision, linearity, limit of detection, and interference resilience; clinical validation involving a diverse cohort of 600 patient samples across multiple sites representing varied demographic and clinical conditions (age, liver function, concomitant medications, dietary vitamin K intake); and a head-to-head comparison against gold-standard laboratory INR measurements. Special attention was given to pre-analytical variables common in low-resource environments, including warm ambient temperatures, sample hemolysis, and inconsistent anticoagulant usage, with the aim of maintaining assay reliability under field conditions. Results demonstrated a high degree of concordance with reference INR measurements (mean bias within 0.1 INR units, intraclass correlation coefficient >0.95) and robust performance across expected warfarin dose ranges (INR 2.0–3.5 for most indications, extending to supra-therapeutic ranges under certain clinical scenarios). The assay achieved clinically acceptable turnaround times (<15 minutes from sample collection to result) and demonstrated reproducibility with coefficients of variation below 6% across runs and operators. Stability studies indicated a shelf-life suitable for deployment in settings with limited cold chain capabilities, and the device operated effectively on rechargeable power sources, addressing electricity reliability issues. Decision-analysis modeling suggested that implementation of the point-of-care assay could reduce hospital visits, shorten time to therapeutic INR, and minimize adverse events by enabling more timely dose adjustments, with cost-effectiveness favorable in high-burden regions when considering reduced laboratory transport costs and improved patient outcomes. User-centered design evaluations highlighted ease of use, minimal training requirements, and acceptance among healthcare workers, along with clear, actionable results compatible with existing warfarin management protocols. Limitations identified include potential variability in thromboplastin activity across cartridge lots and the need for ongoing quality control in decentralized settings. Overall, the study provides a validated, scalable solution for real-time warfarin monitoring, with the potential to enhance therapeutic safety and accessibility in resource-limited clinical settings where conventional laboratory infrastructure is constrained. Future work will focus on expanding the assay to account for emerging anticoagulants and integrating data with centralized patient records for longitudinal anticoagulation management.

Project Overview

What This Project Is About

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A straightforward, beginner-friendly look at a test that checks how well Warfarin is working in patients. The project aims to develop a simple, fast test that can be used in clinics with limited resources to monitor blood clotting control without sending samples to distant labs.

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The Problem It Addresses

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Warfarin therapy needs careful monitoring because it changes how quickly the blood clots. In many low-resource settings, access to standard lab tests is limited or slow, which can lead to unsafe dosing or bleeding risks. The project tackles this gap by proposing a user-friendly, on-site test.

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Objectives of the Project

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1. Explain how warfarin affects blood clotting and why timely tests matter.
2. Design a practical, low-cost coagulation test suitable for clinics with limited equipment.
3. Evaluate the test’s accuracy against standard laboratory tests.
4. Assess ease of use, turnaround time, and potential training needs for staff.
5. Identify limitations and plan steps to address them in real settings.

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What You Will Do Step by Step

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1. Review existing coagulation tests and choose a target measurement (e.g., time to clot) that works with minimal gear.
2. Develop a simple testing protocol and assemble necessary materials that are affordable and available locally.
3. Collect blood samples (with ethical approvals and safety) and run parallel tests with standard methods.
4. Analyze data to compare results, calculate accuracy, sensitivity, and specificity.
5. Test practicality: ease of use, results readability, and time required per test.

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Expected Outcome

Expect a validated, easy-to-use coagulation assay that provides reliable results, enabling safer Warfarin management in resource-limited clinics and potentially reducing adverse events related to improper dosing.