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Porphobilinogen/Creatinine Ratio, Urine

Published: August 9, 2026Updated: August 16, 2026

Measures urinary porphobilinogen relative to creatinine to help evaluate for increased porphobilinogen production, particularly when an acute porphyria is suspected.

Quick summary

["An elevated urine PBG/creatinine ratio may support evaluation for an acute porphyria."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
34357-4
Short code
PBG/Creat Ur-sRto
Synonyms
PBG/Creat 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 urine test measures porphobilinogen (PBG) relative to creatinine. Creatinine is used to account for differences in urine concentration, allowing the laboratory to assess PBG excretion more reliably.

Why might I need this test?

The test may be used when symptoms suggest an acute porphyria, such as severe unexplained abdominal pain, nausea, constipation, weakness, confusion, seizures, or darkening or reddening of the urine.

How is the test performed?

A urine specimen is tested for porphobilinogen and creatinine, and the laboratory calculates the PBG-to-creatinine ratio. The specimen may be collected as a spot urine or according to the laboratory's specific instructions.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional or laboratory. If a timed collection is requested, record the start and end times and collect all urine during that period.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine PBG/Creatinine Ratio

Frequently asked questions

What is porphobilinogen?
Porphobilinogen is a substance formed during heme production. Large amounts in urine can be associated with an acute porphyria.
Why is creatinine included in this urine test?
Urine can range from very concentrated to very dilute. Comparing PBG with creatinine helps account for urine concentration.
Does an elevated result confirm porphyria?
No. An elevated result may support further evaluation for porphyria, but it does not confirm the diagnosis by itself. Your clinician may order additional urine, blood, or genetic tests.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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