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HelpTest Code LAB7465 Porphobilinogen, Quantitative, Random, Urine
Additional Codes
PBGU
Useful For
First-order test for evaluating a suspected acute porphyria: acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria
Testing Algorithm
For more information see:
-The Heme Biosynthetic Pathway
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineShipping Instructions
Ship specimen protected from light.
Necessary Information
Include a list of medications the patient is currently taking.
Specimen Required
Patient Preparation: Patient must not consume any alcohol for at least 24 hours prior to collection.
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 above 5.0.
3. Specimens should be protected from light and frozen immediately following collection.
Specimen Minimum Volume
15 mL
On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318
Send Urine Container-Amber, Frozen
Off-campus collections:
Send Urine Container-Amber
Specimen to be stored/transported at Frozen temp.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen (preferred) | 7 days | LIGHT PROTECTED |
| Refrigerated | 7 days | LIGHT PROTECTED |
Special Instructions
Reference Values
≤1.3 mcmol/L
Day(s) Performed
Monday through Friday
CPT Code Information
84110
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 |
Interpretation
Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, and recommendations for additional testing when indicated and available, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.
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; Stolzel U, Doss MO, Schuppan D. Clinical guide and update on porphyrias. Gastroenterology. 2019;157(2):365-381.e4. doi:10.1053/j.gastro.2019.04.050)
Report Available
2 to 4 daysSpecimen Retention Time
1 weekReject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.