Abstract: A device and method for detecting the presence of a target analyte in a fluid sample are provided. The device can include an inclined capillary tube for transporting a sample fluid containing a sample and functionalized magnetic beads. The functionalized magnetic beads capture the target analyte from the sample fluid. A well is coupled with the inclined capillary tube for containing a developer solution and for receiving the sample fluid. In at least one embodiment a magnet is movably attached to the inclined capillary tube for attracting the magnetic beads of the sample fluid and moving the magnetic beads into the well. A calorimeter is disposed adjacent to the well for receiving heat output from a reaction caused by an enzyme reaction associated with the captured target analyte in the developer solution thereby allowing detection and quantification of the target analyte.