Lamb wave-based blood coagulation test

Blood coagulation tests are a critical part in diagnosis of patients with bleeding disorders and cardiovascular diseases. However, most conventional blood coagulation tests require large and expensive instruments and skilled personnel. Here, we present a simple and low-cost approach to evaluate blood coagulation using Lamb wave-based device. To assess coagulation, we monitored the acoustic streaming of 5 μm fluorescent particles suspended in citrated plasma. Using a Lamb wave, citrated blood plasma and coagulation reagents can be mixed in a few seconds and the viscosity of the droplet increases due to blood coagulation. Then, the acoustic streaming of particles eventually stops, at which the “coagulation time” is defined. As a preliminary test, coagulation time was reduced with increasing calcium concentration from 0 to 25 mM. Prothrombin time results from the Lamb wave-based device were validated by comparing with those of commercial instruments with the correlation coefficient (R²) as 0.9432. Using the Lamb wave for blood coagulation test, the temperature can be controlled as 37 °C simultaneously by modulating experimental conditions. Our device enables lithography-free, simple and low-cost measurement of blood coagulation, which can be applied to clinical settings and developing countries.