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- Coproporphyrin
- Uroporphyrin
Test Includes
Coproporphyrins I and III; uroporphyrins; hepatocarboxylporphyrins; hexacarboxylporphyrins; pentacarboxylporphyrins
Expected Turnaround Time
3 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Information
Related Documents
Specimen Requirements
Specimen
Urine (random); protected from light
Volume
2 mL
Minimum Volume
1.5 mL
Container
12-mL amber plastic transport tube without preservative
Collection
Transfer required aliquot into a LabCorp amber plastic transport tube with amber cap (LabCorp No. 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.
Storage Instructions
Refrigerate and protect from light.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | Unstable |
Refrigerated | 7 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Stored specimen not refrigerated; specimen exposed to light; acid preservative; pH <3
Test Details
Use
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 [003065].
For initial evaluation of porphyrias. Use Porphyrins, Quantitative, 24-Hour Urine [003194] to follow up random urine abnormal results.
Limitations
See Porphyrins, Quantitative, 24-Hour Urine [003194].
Methodology
High-pressure liquid chromatography (HPLC) with fluorometric detection
Reference Interval
• 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
Additional Information
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
Footnotes
1. Woods JS. Altered porphyrin metabolism as a biomarker of mercury exposure and toxicity. Can J Physiol Pharmacol. 1996 Feb; 74(2):210-215.8723034
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 120980 | Porphyrins, Qn, Random U | 120988 | Uroporphyrins (UP) | ug/L | 11228-4 | |
| 120980 | Porphyrins, Qn, Random U | 120989 | Heptacarboxyl (7-CP) | ug/L | 2407-5 | |
| 120980 | Porphyrins, Qn, Random U | 120990 | Hexacarboxyl (6-CP) | ug/L | 27400-1 | |
| 120980 | Porphyrins, Qn, Random U | 120991 | Pentacarboxyl (5-CP) | ug/L | 11221-9 | |
| 120980 | Porphyrins, Qn, Random U | 120992 | Coproporphyrin (CP) I | ug/L | 9343-5 | |
| 120980 | Porphyrins, Qn, Random U | 120993 | Coproporphyrin (CP) III | ug/L | 9345-0 |
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