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HelpTest Code PQNU Porphyrins, Quantitative, 24 Hour, Urine
Ordering Guidance
This 24-hour urine test should be ordered when the specimen will not reach Mayo Clinic Laboratories (MCL) within 72 hours. If the specimen will reach MCL within 72 hours, order PQNRU / Porphyrins, Quantitative, Random, Urine.
Shipping Instructions
Ship specimen in amber container to protect from light.
Necessary Information
1. 24-Hour volume (in milliliters) is required.
2. Patient's sex is required.
3. Collection date and time should be documented upon completion of the 24-hour collection.
4. Include a list of medications the patient is currently taking.
Specimen Required
Patient Preparation: Patient should not consume any alcohol for the 24 hours before, as well as during, specimen collection.
Supplies:
-Urine Container - Amber, 60-mL (T596)
-Sodium Carbonate, 5 gram (T272)
Container/Tube: Amber, 60-mL urine container
Specimen Volume: 20 to 50 mL
Collection Instructions:
1. Add 5 g of sodium carbonate as preservative at start of collection. This preservative is intended to achieve a pH above 7. Do not substitute sodium bicarbonate for sodium carbonate.
2. Collect a 24-hour urine specimen.
3. The container should be refrigerated and protected from light as much as possible during collection.
4. Record volume and duration. An aliquot should be frozen when collection is complete.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Useful For
Preferred screening test for congenital erythropoietic porphyria and porphyria cutanea tarda and during symptomatic periods for acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria when specimen transport will be longer than 72 hours
Testing Algorithm
The following algorithms are available:
Special Instructions
Method Name
High-Performance Liquid Chromatography (HPLC) with Fluorometric Detection/Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Porphyrins, QN, USpecimen Type
UrineSpecimen Minimum Volume
15 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen | 7 days | LIGHT PROTECTED |
Reference Values
Uroporphyrins (Octacarboxyl):
≤30 nmol/24 h
Heptacarboxylporphyrins:
≤9 nmol/24 h
Hexacarboxylporphyrins:
≤8 nmol/24 h
Pentacarboxyporphyrins:
≤10 nmol/24 h
Copropprphyrins (Tetracboxyl)
Males: ≤230 nmol/24 h
Females: ≤168 nmol/24 h
Porphobilinogen:
≤2.2 mcmol/24 h
Day(s) Performed
Monday through Friday
Report Available
2 to 4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84110-Porphobilinogen, quantitative
84120-Porphyrins, quantitation and fractionation
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PQNU | Porphyrins, QN, U | 43116-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TM3 | Collection Duration | 13362-9 |
| VL1 | Urine Volume | 3167-4 |
| 29357 | Uroporphyrin, Octa | 15096-1 |
| 29358 | Heptacarboxylporphyrins | 25434-2 |
| 29359 | Hexacarboxylporphyrins | 25438-3 |
| 29360 | Pentacarboxylporphyrins | 25494-6 |
| 29361 | Coproporphyrin, Tetra | 15041-7 |
| 29362 | Porphobilinogen | 14882-5 |
| 23403 | Interpretation | 59462-2 |
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.