Abnormal urinary organic compound level Elevated urinary porphyrin level 2024-03-16T18:08:46Z The amount of a porphyrin compound in the urine, normalized for urine concentration, is above the upper limit of normal. Porphrins are natural pigments containing a fundamental skeleton of four pyrrole nuclei united through the alpha-positions by four methine groups to form a macrocyclic structure. Porpyrins giove rise to heme and combalamine. Porphyrias are a group of diseases that are clinically and genetically heterogeneous and originate mostly from inherited dysfunctions of specific enzymes involved in heme biosynthesis. Such dysfunctions result in the excessive production and excretion of the intermediates of the heme biosynthesis pathway in the blood, urine, or feces, and these intermediates are responsible for specific clinical presentations. An accumulation of the following two different kinds of metabolites may occur: one is the porphyrin precursors, such as 5-aminolevulinic acid (ALA) and porphobilinogen (PBG), which are linear non-fluorescent molecules, and the other kind is the porphyrins, such as uroporphyrins (URO), coproporphyrins (COPRO), and protoporphyrins (PROTO), which are circular molecules that emit fluorescence signals when excited. Porphyrins are the oxidized products of porphyrinogens, which are the actual substrates of the enzymes involved in heme biosynthesis. Porphyrins exist in different isomers depending on the arrangement of the substituents acetate (A), propionate (P), methyl (M), and vinyl (V) of the four pyrroles of the porphyrin ring.