Porphobilinogen/Creatinine Ratio, 24-Hour Urine
Measures porphobilinogen in a 24-hour urine collection and adjusts the result using urine creatinine.
An elevated result may indicate increased heme production, as can occur during an acute porphyria attack.
Key facts at a glance
- LOINC
- 74441-7
- Short code
- PBG/Creat 24h Ur-sRto
- Synonyms
- PBG/Creat 24h Ur-sRto
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test measures porphobilinogen (PBG), a substance produced during the body's production of heme, in urine collected over 24 hours. The result may be interpreted in relation to the urine creatinine concentration.
Why might I need this test?
Urinary porphobilinogen is often evaluated when symptoms suggest an acute porphyria, such as severe abdominal pain, nausea, weakness, or neurologic symptoms. It may also be used to monitor people with a known porphyria.
How is the test performed?
You collect all urine produced during a full 24-hour period. The laboratory measures porphobilinogen in the collection and may compare it with the creatinine concentration to account for variations in urine concentration.
How do I prepare for the test?
Follow the collection container and timing instructions provided by the laboratory. Usually, you discard the urine present at the start time, then collect every subsequent urine sample for exactly 24 hours, including the final sample. Record the total volume and refrigerate or deliver the sample as instructed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated urinary porphobilinogen result can occur with acute porphyrias, particularly during an attack, and may also be seen in some other conditions that increase heme production. Creatinine adjustment helps account for differences in urine concentration, but symptoms, other laboratory results, and confirmatory testing are needed for interpretation.
Short name
24-Hour Urine Porphobilinogen
Frequently asked questions
What does a high porphobilinogen result mean?
Why is urine creatinine included?
Can this test be collected at home?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy