Sequentioning is the most accurate method of nucleic acid analysis, allowing us to determine the sequence of nucleotides in the fragment of DNA being tested. It consists in decomposing of products obtained by means of PCR in a capillary sequencer. The products are marked with fluorescent dyes which enables their identification. The detection takes place using a laser which guarantees very high sensitivity of the method. It is used mainly to determine the sequence of genes being tested (human genes or genes coming from microorganisms).