Systems and devices for real time health status credentialing

An external device for estimating a core body temperature of a human subject, the device comprising:

• a casing sized and shaped to fit onto a wrist of a human subject, the casing having:
• a first face and a second face;
• a heat trap located in the casing, the heat trap located adjacent to the first face of the casing and having an opening oriented to receive thermal energy from a wrist of a wearer, the heat trap having a domed shell comprising a thermal-insulation material, the shell having an inner thermal energy-reflective surface;
• a first temperature sensor extending into or along the domed shell to measure a temperature within the heat trap;
• a second temperature sensor at a peripheral region of the casing;
• a microprocessor receiving inputs from the first and second sensors at preset intervals and converting the inputs to digital form;
• a transmitter in receiving digital inputs from the microprocessor and transmitting temperature data.