This invention discloses a thermal envelope including a pouch and a flap that closes the pouch and a thermal capacitance material that lines the pouch, wherein the thermal capacitance material has an initial temperature in a temperature range of -5 DEG C to 20 DEG C, characterized by the thermal capacitance material having a thermal capacitance that maintains a temperature of the medical sample placed in the pouch within the temperature range during a period of time not more than 7 hours from the time the medical sample was placed in the pouch. A method for sending a medical sample from a sampling site to a laboratory is also disclosed.
