Porphyrins, Quantitative, Random Urine

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Turnaround Time: 3 - 5 days
CPT Code:

84120

Test Type: 2 mL Urine (random); protected from light
Stability Time:

Temperature

Period

Room temperature

Unstable

Refrigerated

7 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Reference Range:

• Coproporphyrin (CP) I: 0−15 μg/L

• Coproporphyrin (CP) III: 0−49 μg/L

• Heptacarboxylporphyrins (7-CP): 0−2 μg/L

• Hexacarboxylporphyrins (6-CP): 0−1 μg/L

• Pentacarboxylporphyrins (5-CP): 0−2 μg/L

• Uroporphyrins (UP): 0−20 μg/L

Overview:

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 [003053].

For initial evaluation of porphyrias. Use Porphyrins, Quantitative, 24-Hour Urine [003194] to follow up random urine abnormal results.

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.1

1. Woods JS. Altered porphyrin metabolism as a biomarker of mercury exposure and toxicity. Can J Physiol Pharmacol. 1996 Feb; 74(2):210-215. PubMed 8723034

Collection Details:

Collection Instructions:

12-mL amber plastic transport tube without preservative.

Transfer required aliquot into a LabCorp amber plastic transport tube with amber cap (LabCorp N° 23598). (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.