Implementation of the Prothrombin Time test in the Spinit® point of care platform

Sofia Rodrigues Vaz

Key information

Authors:

Sofia Rodrigues Vaz (Sofia Rodrigues Vaz)

Supervisors:

João Manuel de Oliveira Garcia da Fonseca; Pedro Miguel Félix Brogueira (Pedro Miguel Félix Brogueira)

Published in

03/01/2016

Abstract

The prothrombin time blood assay is used by health specialists in the detection of cardiovascular anomalies, considered the leading cause of death in the world by the World Health Organisation. Conventional clinical testing is time consuming, requires complex sample handling, and is prone to errors. However, recent technological advances have allowed the development of automatic, small, portable point of care (PoC) devices, that operate with small sample volumes, and can give results within minutes. The present study proposes the integration of the prothrombin time assay in the spinit centrifugal microfluidic platform, taking advantage of its photoelectric detection module, which allows to detect optical changes through paired emitter-detector diode (PEDD) based spectrophotometry. The optical signal variation detected during fibrin formation was studied, and different relations were found between the spinit output and the prothrombin time in international normalised ratio units (PT-INR) . Several reagents were tested, the centrifugation protocol was optimised, and the optical system definitions were changed, in order to find the detection chamber as fast as possible. Finally, the performance of different microfluidic mixing structures was evaluated experimentally, using plasma calibrators. Structure 24 from the 4th mixing layout tested allowed to obtain the best results, with coefficients of variation lower than 6% for all the calibrators, for all the time references considered.