a 45-microl aliquot of urine is oxidized with 3 mmol/l iodine in 3 mol/l hcl to convert porphyrinogens to porphyrins , and then decolorized with 5 ml of 0.45 mmol/l sodium thiosulfate .
C0032711
porphyrinogens
C0032712
porphyrins