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HelpOrder Code LAB1363 Porphyrins, Quantitative, 24 Hour, Urine
Additional Codes
| Mayo Test ID |
|---|
| PQNU |
Reporting Name
Porphyrins, QN, UUseful 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
Specimen Type
UrineOrdering 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.
Specimen Minimum Volume
15 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen | 7 days | LIGHT PROTECTED |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.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
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Day(s) Performed
Monday through Friday
Method Name
High-Performance Liquid Chromatography (HPLC) with Fluorometric Detection/Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
CPT Code Information
84110-Porphobilinogen, quantitative
84120-Porphyrins, quantitation and fractionation
Testing Algorithm
The following algorithms are available:
Special Instructions
Genetics Test Information
This test is preferred during symptomatic periods for acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria when specimen transport will be longer than 72 hours. If the specimen will be received at Mayo Clinic Laboratories within 72 hours of collection, PQNRU / Porphyrins, Quantitative, Random, Urine is recommended.
Testing includes porphobilinogen, which is useful in the evaluation of the acute porphyrias.
This is the preferred test to begin assessment for congenital erythropoietic porphyria and porphyria cutanea tarda.
Method Description
An aliquot of urine is acidified and mesoporphyrin is added as an injection marker. Porphyrins in the acidified urine are separated by high-performance liquid chromatography, and the eluted porphyrins are quantified by comparison of their fluorescence intensity to that of known porphyrin standards.(Ford RE, Ou CN, Ellefson RD. Liquid chromatographic analysis for urinary porphyrins. Clin Chem. 1981;27[3]:397-401; de Andrade VL, Mateus ML, Aschner M, Dos Santos AM. Assessment of occupational exposures to multiple metals with urinary porphyrin profiles. J Integr OMICS. 2018;8(1):216. doi:10.5584/jiomics.v8i1.216)
Porphobilinogen (PBG) in urine is quantified by liquid chromatography tandem mass spectrometry after addition of stable isotope-labeled PBG internal standard and solid-phase extraction.(Ford RE, Magera MJ, Kloke KM, et al. Quantitative measurement of porphobilinogen in urine by stable-isotope dilution liquid chromatography-tandem mass spectrometry. Clin Chem. 2001;47[9]:1627-1632; Louleb M, Galvan I, Latrous L, et al. Detection of porphyrins in hair using capillary liquid chromatography-mass spectrometry. Int J Mol Sci. 2022;23[11]:6230.
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.