Method and apparatus for the detection of biological material on non-living surfaces in which samples are exposed to electromagnetic radiation of specific energies capable of exciting various intrinsic fluorophores, and these fluorophores emit fluorescence that can be measured. The signal from the background, scattered excitation light and reflected excitation light is removed from the fluorescence signals due to the intrinsic fluorophores from the biological material and the intensities of the signals from the intrinsic fluorophores are required to lie within expected ranges.