This article describes an acoustic microagitator for being used in biological fluids analysis. It is known that a piezoelectric transducer, with its vibration, can be used for mixing fluids. However, in this case, the piezoelectric transducer is also used to heat the samples, improving the reaction of fluids that benefit from that effect. The piezoelectric transducer is fabricated from a poly(vinylidene fluoride) polymer, in the beta phase (β-PVDF). This concept is demonstrated theoretically and by measuring the temperature profile in a regular 1 cm optical lightpath glass cuvette, using capillary thermocouples. This system can further be included in a lab-on-a-chip device, acting as a microreactor, for clinical diagnosis.