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Methadone/Creatinine Ratio, Urine

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

A urine test that measures methadone relative to creatinine, helping assess medication levels while accounting for urine concentration.

Quick summary

["This ratio can help clinicians monitor methadone therapy and identify possible nonadherence, dose changes, or drug accumulation."]

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

Key facts at a glance

LOINC
41466-4
Short code
Methadone/Creat Ur
Synonyms
Methadone/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 methadone in urine compared with the amount of creatinine. Creatinine is used as a marker of urine concentration, so the ratio can help interpret methadone levels even when urine is more or less diluted.

Why might I need this test?

Clinicians may use this test during methadone treatment to monitor medication exposure, evaluate adherence, or investigate symptoms suggesting that the dose is too low or too high. It may also be used when urine drug testing is needed for medication monitoring.

How is the test performed?

A urine sample is collected and tested in the laboratory for methadone and creatinine. The laboratory calculates the methadone-to-creatinine ratio; some urine drug screens are also confirmed with a more specific laboratory method.

How do I prepare for the test?

Follow the instructions provided by your clinician or testing facility. Take methadone consistently as prescribed and do not change or withhold doses unless your clinician directs you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine Methadone/Creatinine Ratio

Frequently asked questions

Does this test show whether I am taking methadone as prescribed?
It can provide evidence of methadone exposure and help assess adherence, but a single result cannot determine adherence by itself. Dose timing, metabolism, hydration, and other medications can also affect the result.
Why is creatinine included in the result?
Creatinine helps show how concentrated the urine is. Comparing methadone with creatinine makes the result less dependent on urine concentration than reporting methadone alone.
What if my result is unexpectedly high or low?
Your clinician will interpret the result alongside your dose, when the sample was collected, symptoms, and other relevant findings. Do not adjust your methadone dose without medical guidance.
  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