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Uroporphyrin-to-Creatinine Ratio, Urine

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

This urine test measures uroporphyrin relative to creatinine, helping evaluate possible disorders of heme production while accounting for urine concentration.

Quick summary

["The result helps determine whether an unusual amount of uroporphyrin is being excreted in the urine."]

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

Key facts at a glance

LOINC
45319-1
Short code
Uropor/Creat Ur-sRto
Synonyms
Uropor/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 test measures uroporphyrin, a type of porphyrin, in urine and compares it with the amount of creatinine in the same sample. Creatinine is used as a reference because its level varies with urine concentration.

Why might I need this test?

A clinician may order it when symptoms suggest a porphyria or another condition that affects heme production. It may also be used to evaluate unexplained changes in urine color or symptoms involving the skin, abdomen, or nervous system.

How is the test performed?

A urine sample is collected and analyzed in the laboratory. The report provides the amount of uroporphyrin relative to the amount of creatinine in that sample.

How do I prepare for the test?

No special preparation is usually required for a routine urine sample, but follow the laboratory's collection instructions. The time of collection, fluid intake, and whether a first-morning or timed specimen is required can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine uroporphyrin/creatinine ratio

Frequently asked questions

Why are uroporphyrin and creatinine measured together?
Urine becomes more or less concentrated depending on fluid intake and other factors. Comparing uroporphyrin with creatinine helps reduce the effect of urine concentration on the result.
Does an abnormal result mean I have a porphyria?
Not necessarily. Porphyrin levels can also be affected by liver disease, medications, alcohol use, and other conditions, so additional testing may be needed.
What if my urine sample is very dilute?
A dilute sample can make the measured ratio less reliable. The laboratory or clinician may request another sample, often as a first-morning urine specimen, if collection conditions are unsuitable.
  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