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Orderable Name PQNU Porphyrins, Quantitative, 24 Hour, Urine

Additional Codes

CNE Order Code: U24 Porphyrin

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:

-Porphyria (Acute) Testing Algorithm 

-Porphyria (Cutaneous) Testing Algorithm 

Specimen Type

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.


Specimen 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

CPT Code Information

84110-Porphobilinogen, quantitative

84120-Porphyrins, quantitation and fractionation

Report Available

2 to 4 days

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

High-Performance Liquid Chromatography (HPLC) with Fluorometric Detection/Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Urine Preservative Collection Options

Note: The addition of preservative must occur prior to beginning the collection.

Ambient (no additive)

No

Refrigerate (no additive)

No

Frozen (no additive)

No

50% Acetic Acid

No

Boric Acid

No

Diazolidinyl Urea

No

6M Hydrochloric Acid

No

6M Nitric Acid

No

Sodium Carbonate

Required

Thymol

No

Toluene

No

**Protect specimen from light.