flame photometry [L, flagrare, to burn; Gk, phos, light, metron, measure] , measurement of the wavelength of light rays emitted by excited metallic electrons exposed to the heat energy of a flame, used to identify characteristics in clinical specimens of body fluids. The intensity of the emitted light is proportional to the concentration of atoms in the fluid, and a quantitative analysis can be made on that basis. In the clinical laboratory, flame photometry was once used to measure sodium, potassium, and lithium levels but is no longer used routinely.
