Porphobilinogen, Quantitative, 24-Hour Urine
Also known as: PBG
Use
Quantitative urinary measurement of porphobilinogen (PBG) is useful in the evaluation of acute porphyrias. Elevated PBG excretion during symptomatic periods supports the biochemical diagnosis of acute porphyria such as acute intermittent porphyria, hereditary coproporphyria, or variegate porphyria ([dlmp.uw.edu](https://dlmp.uw.edu/test-guide/view/UPBG?utm_source=openai)).
Special Instructions
Specimen must be a 24‑hour urine collection adjusted to pH 6‑7 with 5 g sodium carbonate added at the start. Specimen must be protected from light (e.g., collected in amber jug or wrapped in aluminum foil) and refrigerated during collection. Whenever possible, specimen should be collected during an acute episode. PBG may degrade upon remission or exposure to UV light/ambient temperature ([laboratoryalliance.com](https://www.laboratoryalliance.com/tests/display/3268?utm_source=openai)).
Limitations
Not provided.
Methodology
Mass Spectrometry
Biomarkers
Result Turnaround Time
4-7 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
2 mL from 24-hour urine
Minimum Volume
1 mL
Container
Plastic leak‑proof container, 24‑Hour Urine Collection Container, protected from light (amber jug or wrapped in foil)
Collection Instructions
Collect 24‑hour urine; adjust pH to 6‑7 with 5 g sodium carbonate at start; protect from light and refrigerate during collection.
Causes for Rejection
Not protected from light
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 7 days |
| Frozen | 30 days |