Porphyrins, quantitative, random urine-13518
Test info
Uroporphyrin
- Coproporphyrin (CP) I
- Coproporphyrin (CP) III
- Heptacarboxylporphyrins (7-CP)
- Hexacarboxylporphyrins (6-CP)
- Pentacarboxylporphyrins (5-CP)
- Uroporphyrins (UP)
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.
For initial evaluation of porphyrias. Use Porphyrins, Quantitative, 24-hour urine [13486] to follow upabnormal random urine results.
Specimen
- Transfer 2mL of to a Amber screw-cap polypropylene frozen transport tube/vial - 4mL (LabCorp)
- Freeze
Protect from light
Frozen (preferred) - 14 days
Freeze/thaw cycles - stable x3
Refrigerated - 7 days
Ambient - NO
- Stored specimen not refrigerated
- Specimen exposed to light
- Acid preservative
- pH <3
Performance
High-pressure liquid chromatography (HPLC) with fluorometric detection
Clinical and Interpretive info
| 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 |
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. Both in experimental animals and in humans exposed to heavy metals, elevated levels of porphyrins have been found in urine.