A microfluidic test module for detecting target nucleic acid sequences in a fluid, the test module having an outer casing configured for hand-held portability, the outer casing having an inlet for receiving the fluid containing the target nucleic acid sequences, a hybridization chamber mounted in the casing, the hybridization chamber containing electrochemiluminescent (ECL) probes for detecting the target nucleic acid sequences, each of the ECL probes having an ECL luminophore for emitting photons when in an excited state and a functional moiety for quenching photon emission from the ECL luminophore by resonant energy transfer, and electrodes for receiving an electrical pulse to excite the ECL luminophores, wherein, the hybridization chamber has a volume less than 900,000 cubic microns.