Abstract Background Excessive bleeding is prevalent in severe trauma patients, and measurement of multiple coagulation parameters is vital to correcting coagulopathy and improving outcomes. There are no rapid, near-patient technologies that can perform multiple coagulation assays simultaneously on a single consumable. We are developing a point-of-care digital microfluidic (DMF) platform to test three critical coagulation markers: prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen. Methods Five proficiency testing plasma samples were obtained from the College of American Pathologists (CAP) with normal, intermediate, and prolonged response of PT and aPTT, and normal and elevated fibrinogen levels. After loading 10 μL of sample onto the cartridge, autonomous digital microfluidic operations divided the sample into three droplets, which were then combined with reagents for PT, aPTT or fibrinogen. The viscosity of these droplets, measured from the electrical impedance on a toaster-sized instrument, changes at a rate proportional to the amount of coagulation precursors present from which time/activity was calculated. Results Classification of samples into normal, intermediate or prolonged categories along with the respective times obtained from the DMF cartridges matched those obtained on the Stago Compact Max instrument (Figure). We also demonstrated separation of plasma from whole blood within the DMF cartridge using agglutinating reagents, enabling an easy-to-use workflow without the need for centrifugation. Conclusions Our preliminary results demonstrate that PT, aPTT and fibrinogen can be measured on a single cartridge with performance similar to comparator methods, with a time to result of <15 minutes. To our knowledge, this is the first time these 3 assays have been performed simultaneously on a single consumable and furthermore, this is the first time viscoelastic tests have been performed on a multifunctional instrument that also performs chemistry and molecular tests. Studies are underway to evaluate analytical and clinical performance.
Read full abstract