In intermittent porphyria, what is present in the urine:

Porphyria is diagnosed through spectroscopy and biochemical analysis of blood, urine, and stool.In general, urine estimation of porphobilinogen (PBG) is the first step if acute porphyria is suspected.As a result of feedback, the decreased production of heme leads to increased production of precursors, PBG being one of the first substances in the porphyrin synthesis pathway. In nearly all cases of acute porphyria syndromes, urinary PBG is markedly elevated except for the very rare ALA dehydratase deficiency or in patients with symptoms due to hereditary tyrosinemia type I.