A a patch is provided for application against the skin of a user. The patch includes a substrate, a material detector, a memory, a comparator, a three state indicator and a power source. The material detector is disposed on the substrate, has a contact portion disposed so as to contact the skin, and can generate a material signal based on an amount of material contacting the contact portion. The memory has a priori material data stored therein. The comparator outputs a compared signal based on a comparison of the material signal and the a priori material data. The three state indicator provides an indication of the state of the user based on the compared signal, wherein the indication being selected from one of the group consisting of a first indication of a first state, a second indication of a second state and a third indication of a third state. The power source provides power to the three state indicator.
