Detection techniques can vary in both direct and amplified methodologies and can include labeling either the probe or the target molecule of interest:
Chemiluminescence: Release of light energy at the end of a chemical reaction that is detected by a luminometer. Uses a label such as acridinium ester.
Electrophoresis: movement in a matrix such as a gel that is caused by an electrical field.
Enzyme: Uses enzyme and substrate principles to label the appropriate target or probe. Can be combined with fluorescence or dyes for detection.
Fluorescence: Molecules that emit light at a longer wavelength when excited at a shorter wavelength. Detection techniques include fluorescent staining of nucleic acids as well as fluorescent labeled probes that are measured in a fluorometer or with fluorescent polarization.
Radioactivity: Uses a labeling technique where the radioactive label is then measured in a scintillation counter. The earliest assays utilized radioactive decay.