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Normeperidine/Creatinine Ratio, Urine

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

Measures the amount of normeperidine, a meperidine metabolite, relative to urine creatinine to help assess drug exposure.

Quick summary

["This urine test helps evaluate exposure to the opioid pain medicine meperidine (Demerol)."]

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

Key facts at a glance

LOINC
58387-2
Short code
Normeperidine/Creat Ur
Synonyms
Normeperidine/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 normeperidine, an active metabolite of the opioid pain medicine meperidine (Demerol), relative to the amount of creatinine in the same urine sample. The ratio helps account for differences in urine concentration.

Why might I need this test?

It may be ordered when meperidine use is suspected, especially during treatment monitoring, after an overdose, or when a patient has reduced kidney function. It can help clinicians estimate how much normeperidine the body has formed.

How is the test performed?

A urine specimen is collected and analyzed in a laboratory. The laboratory measures normeperidine and creatinine and calculates their ratio. The specimen may be a random collection or a timed collection, depending on the instructions provided by your clinician.

How do I prepare for the test?

Follow your clinician's instructions about when and how to collect urine. Fasting is generally not required, but tell the healthcare team about all medicines you take, including meperidine and any medicines that can affect urine collection or kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine normeperidine-to-creatinine ratio

Frequently asked questions

What is normeperidine?
Normeperidine is an active metabolite formed when your body breaks down meperidine (Demerol). It can build up when meperidine exposure is high or kidney function is reduced.
Why is creatinine included in the result?
Creatinine is used as an adjustment for urine concentration. Including it makes the normeperidine result more comparable across urine samples that may be more or less concentrated.
Does this test show how much meperidine I have taken?
No. It measures normeperidine, not meperidine itself, and reflects both meperidine exposure and how the body metabolizes and clears the drug. Your clinician interprets it alongside your medication history and clinical condition.
  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