We have also explored heaters with temperature profiles suitable for other isothermal amplification techniques requiring different incubation temperatures, e.g., the Exponential Amplification Reaction (EXPAR), Nicking Enzyme Amplification Reaction (NEAR), or Recombinase Polymerase Amplification (RPA), could be integrated with this method. These prototypes are not significantly different in form, but use different EPCMs, and in one case a different exotherm. A CaO heater with a different EPCM formulation has been shown to yield a temperature profile suitable for EXPAR with a nominal temperature of 55uC ( Figure 4A ). Evaluation with EXPAR reactions are in process. We have also explored a similar heater approach with sodium acetate (NaAc, Figure 4B ). Hand warmers based on the crystallization reaction of NaAc are common. In a purified form, at typical ambient temperatures, liquid NaAc is thermodynamically unstable but kinetically stable due to the absence of nucleating sites for crystal formation. The application of a mechanical shock initiates the exothermic crystallization, and when mixed as a 25% aqueous solution the phase change occurs repeatably at ,37uC. In this system, NaAc acts as both the exothermic reactant and the EPCM. This system has the advantage of being regenerable (immersion of the NaAc in boiling water is sufficient). For isothermal amplification methods operating at temperatures below 45uC as well as for other diagnostic applications requiring heating (e.g., smart-polymer-based analyte pre-concentration [30] ), NaAc is the preferred exothermic/ phase change system. These results establish that the heater is a flexible platform for a number of isothermal detection techniques.