There are provided an indirect internal reforming-type SOFC in which a reformer is heated by radiation heat from a SOFC, wherein the heat receiving area of a reformer can be easily made large and stable operation is possible without decreasing the efficiency, and a reformer suitable to the SOFC. In one embodiment, the device includes a substrate having a top surface with a first lattice constant. This method can be use to diagnose illnesses such as, but not limited to, sepsis, necrotizing enterocolitis, pneumonia and meningitis.