Meperidine/Creatinine Ratio, Urine
A urine test that measures the opioid pain medicine meperidine relative to urine creatinine, which helps account for differences in urine concentration.
["This test can help determine whether meperidine is present in the body and may be used to monitor medication use or drug exposure."]
Key facts at a glance
- LOINC
- 58386-4
- Short code
- Meperidine/Creat Ur
- Synonyms
- Meperidine/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 meperidine, a prescription opioid pain medicine, in urine. The result is compared with the amount of creatinine in the same urine sample. Creatinine is used as a reference because its level can help account for how concentrated or dilute the urine is.
Why might I need this test?
A clinician may order this test to check for meperidine exposure, monitor use of the medication, assess adherence to prescribed treatment, or investigate possible drug use. It may also be used in situations involving suspected opioid intoxication or medication diversion.
How is the test performed?
A urine sample is collected and analyzed in a laboratory to determine the amounts of meperidine and creatinine. The laboratory then reports the meperidine-to-creatinine ratio or the individual measurements, depending on the ordered test.
How do I prepare for the test?
Follow the laboratory or clinician's instructions for collecting the urine sample. Tell the clinician when you last took meperidine, because timing and dose can affect the result. Do not intentionally drink large amounts of water or withhold urine unless specifically instructed to do so.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detecting meperidine confirms that the medication or a related compound was present in the urine at the time of collection. A higher ratio may reflect a larger dose, recent use, or concentrated urine, while a lower ratio may reflect earlier use or diluted urine. The result should be interpreted with the timing of the last dose, kidney function, clinical findings, and other relevant tests.
Short name
Urine meperidine
Frequently asked questions
Does this test show how much meperidine I took?
Why is creatinine included in the result?
How long after taking meperidine can it be detected in urine?
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