An embodiment provides an apparatus, including: a cartridge including a base and a lid; at least one fluid line located between the base and the lid of the cartridge; at least one heating element located either on the base or the lid and aligned in intimate contact with the at least one fluid line; at least one heat sensing element in intimate contact with the at least one fluid line, where the at least one heat sensing element is spaced downstream from the at least one heating element; a supply of power to the cartridge; and a processor in electrical communication with the cartridge that executes a program of instructions to: operate the at least one heating element to produce heating of the at least one fluid line at a first position; and operate the at least one heat sensing element to detect the heat of a fluid within the at least one fluid line at a position downstream of the first position. Other embodiments are described and claimed.