[Urinary porphyrin screening tests].

While it is known that urinary porphyrins are invariably increased in all varieties of porphyrias, no analytical device, color-developing solution or test paper for specific use in quantifying porphyrins is as yet available. Determination of porphyrins, requiring highly specialized technical skill and experience, is now being done, only in a limited number of special laboratories. For this reason, porphyrias in so many instances are detected late in the course of disease and few physicians are aware of the necessity for making porphyrin measurement. Of greatest importance in the diagnosis of porphyrias is the urinary screening test for porphyrins and screening tests reported to date, though not in widespread use, include those that make use of spectrum, argon ion laser, thin-layer chromatography and ion exchange column chromatography. In this paper, an account is given of three methods currently in most extensive use, i.e. the Schwartz method, Brugsh-Fischer method and high-performance liquid chromatography method, and microplate fluorescence technique, recently developed by the author.