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Normorphine-to-Creatinine Ratio, Urine

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

A urine test that measures the normorphine metabolite relative to creatinine, which helps account for differences in urine concentration.

Quick summary

["This test can help evaluate recent exposure to morphine or morphine-producing opioids."]

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

Key facts at a glance

LOINC
101223-6
Short code
Normorphine/Creat Ur
Synonyms
Normorphine/Creat Ur
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 normorphine in urine relative to creatinine. Normorphine is a metabolite formed when the body breaks down morphine, and the ratio helps reduce the effect of variations in urine concentration.

Why might I need this test?

It may be used when monitoring opioid use, supporting an evaluation for possible drug exposure, or confirming results from a broader drug screen. A clinician should interpret it alongside the other findings.

How is the test performed?

A urine sample is collected and analyzed to determine the amounts of normorphine and creatinine. The laboratory then calculates their ratio.

How do I prepare for the test?

Follow any instructions provided by the ordering clinician or testing site. The person collecting the sample should be told about all medicines and drugs used, because some can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine normorphine-to-creatinine ratio

Frequently asked questions

What does normorphine detect?
Normorphine is a metabolite of morphine. Its presence may reflect exposure to morphine or certain other opioid drugs that are converted to morphine.
Why is creatinine included in the result?
Creatinine is used to account for how concentrated the urine is. Dividing normorphine by creatinine makes results more comparable between samples.
Can this test show exactly when a drug was used?
No. Urine results generally reflect recent exposure but cannot determine the exact dose, timing, or route of use. A clinician must interpret the result with the medical history and other 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