[The screening diagnosis of porphyria cutanea tarda]

A method is proposed which gives an idea of the type of the absorption spectra of the total porphyrines in the urine without requiring its recording. A single portion of 0,2 ml of urine is mixed with 1,8 ml of IM HCL. The extinctions at 380, 401, 405 and 430 nm are read. The doubled real extinctions (2RE) at 401 and 405 are calculated by the formulae 2RE401--(E380 + E430) and 2E405--(E380 + E430). The extinctions at 380 and 430 outline the "background" of substances which are not porphyrines. When using Spekol 10 the results are multiplied by 1,6 and for Spekol II--they are multiplied by 1,4. 204 patients, 173 of them suffering from porphyria cutanea tarda, were examined by this method and it was established that when the values of 2RE405 exceed 0,060 and are greater than those of 2RE401 uroporphyrine exceeds coproporphyrine and the total porphyrine excretion is above 270 micrograms/l which indicates with great probability an active phase of porphyria cutanea tarda and implies a quantitative determination of the porphyrines.