In recent years, there have been no new commercial developments in identification methods for the clinical chemical laboratory. We are still faced, however, with the problem of ensuring accurate identification. By using a model, the importance of reliable identification can be shown mathematically. The complete identification of a sample is based on a five point identification statement. As a rule, appropriate measures are taken to abridge this identification process, depending on the local situation. The terminology of identification processes is defined and the presently available techniques are discussed.