Abstract: A method for the detection of normal or abnormal constituents in cells, tissues or organisms, including proteins and nucleic acids, is provided which comprises obtaining a spectrographic waveform pattern of the absorption or perturbation of electromagnetic radiation caused by a nucleic acid, protein, cell, tissue or organism suspected of having an abnormal condition and comparing the pattern with the spectrographic waveform pattern of the absorbance or perturbance of the same radiation by the normal or standard object so as to detect the presence or absence of the abnormality. The method can also be used in a number of diagnostic applications such as sorting of cells by conformational or other differences, such as male from female sperm cells. An apparatus is also provided for carrying out these methods.