A LOC device having a supporting substrate, primer-linked, stem-and-loop probes, each with a nucleic acid sequence that matches one of a plurality of target nucleic acid sequences, and a primer for elongating against the target nucleic acid sequence to form a complementary sequence such that during use the nucleic acid sequence matching the target nucleic acid sequence anneals to the complementary sequence to change a fluorescence emission from the probe in response to an excitation light, a polymerase chain reaction (PCR) section for amplifying the target nucleic acid sequences in the fluid prior to hybridization with the FRET probes, and, CMOS circuitry on the supporting substrate, the CMOS circuitry having operative control of the excitation light.