Porphyrins, Quantitative, Urine
Urine porphyrins are useful for the evaluation of cutaneous photosensitivity to exclude porphyria cutanea tarda (PCT). Evaluation of neurologic and/or psychiatric symptoms associated with acute porphyrias, such as acute intermittent porphyria (AIP), requires urine porphobilinogen (PBG) testing. Refer to Porphobilinogen (PBG), Quantitative, Random Urine .
Urine (random); protected from light.
Excess urinary porphyrin excretion, or porphyrinuria, results from inhibition of key enzymatic steps in such clinical conditions as genetic deficiencies in heme production enzymes, hepatitis, renal disease, and erythroid disease, as well as by heavy metal inhibition of heme enzyme synthesis.1 Both in experimental animals and in humans exposed to heavy metals, elevated levels of porphyrins have been found in urine.
12-mL amber plastic transport tube without preservative
Transfer required aliquot into a amber plastic transport tube with amber cap (If amber transport tubes are unavailable, cover transport tube completely, top and bottom, with aluminum foil. Identify specimen with patient’s name directly on the amber transport tube and on the outside of the aluminum foil. Secure with tape.) Specimen must be kept refrigerated during transport.
Refrigerate and protect from light.
Stored specimen not refrigerated; specimen exposed to light; acid preservative; pH <3