Mephenidate/Creatinine Ratio, Urine
A urine test that measures mephenidate relative to creatinine, helping assess drug excretion while accounting for urine concentration.
["This test can help determine whether mephenidate is being excreted in the urine and may support monitoring of prescribed use."]
Key facts at a glance
- LOINC
- 72792-5
- Short code
- Me-phenidate/Creat Ur
- Synonyms
- Me-phenidate/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 the amount of mephenidate, also called Ritalin, in urine relative to the amount of creatinine. Creatinine is a waste product produced by the muscles and is commonly used to help account for differences in urine concentration.
Why might I need this test?
A clinician may order this test to assess recent mephenidate exposure or monitor treatment. It may also be used when there is concern about taking more than prescribed, although urine results alone cannot establish how a medication was taken.
How is the test performed?
A urine sample is collected and analyzed in the laboratory. The laboratory measures mephenidate and creatinine and may calculate their ratio, sometimes called a creatinine-normalized result.
How do I prepare for the test?
Follow the collection instructions provided by your clinician or laboratory, including whether a timed or first-morning urine sample is required. Do not change your mephenidate dose or intentionally withhold medication unless your clinician instructs you to do so.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detectable urine mephenidate indicates that the drug or its metabolites were present in the urine at the time of collection. The creatinine-normalized ratio can help compare results when urine concentration varies, but interpretation depends on the test method, collection time, dose, timing, and individual factors. Results should be reviewed together with the prescribing clinician's assessment.
Short name
Urine mephenidate/creatinine ratio
Frequently asked questions
Does a detectable result mean I am taking too much Ritalin?
Why is creatinine included in the test?
How long before collection does the medication need to be present 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