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Test Code PORPHOB Porphobilinogen, Quantitative, Random, Urine

Reporting Name

Porphobilinogen, QN, Random, U

Useful For

First-order test for evaluation of a suspected acute porphyria: acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria

Specimen Required

Supplies: Urine Container-Amber, 60 mL (T596)

Specimen Volume: 20 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative necessary but pH must be >5.0.

3. Specimens should be frozen immediately following collection and protected from light.

Specimen Type


Specimen Minimum Volume

15 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 7 days
  Refrigerated  7 days

Day(s) and Time(s) Performed

Monday through Friday; 8 a.m.

Seattle Children's Hospital Note:

TAT: 4 - 8 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis

Method Description

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 September;47[9]:1627-1632)

Reference Values

≤1.3 mcmol/L

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
PBGU Porphobilinogen, QN, Random, U 2811-8


Result ID Test Result Name Result LOINC Value
29365 Porphobilinogen, U 2811-8
29366 Interpretation (PBGU) 59462-2
35032 Reviewed By 18771-6

Reject Due To









Testing Algorithm

The following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm


New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.