Metals, toxins and medication
Methadon (EDDP)
A urine test for EDDP, the breakdown product of methadone; shows whether someone has taken methadone in the past few days.
Everything about this testWhat it measures
Methadone is an opioid that is mainly prescribed in the treatment of addiction to heroin or other opioids, and sometimes for severe pain. The liver breaks methadone down into, among other things, EDDP, which leaves the body in the urine. This screening test is an immunoassay that looks for EDDP, with a cut-off of 100 µg/l. Because EDDP is only formed in the body, a positive result shows that methadone was actually taken and not just added to the urine.
- Intake of methadone in the past few days, with or without a prescription
Positive
A positive result means there is EDDP in the urine above the laboratory's cut-off: methadone has been taken in the past few days. Methadone stays in the body for a long time; according to the Farmacotherapeutisch Kompas, it takes 19 to 55 hours for half of it to disappear, so the test usually stays positive for a few days after the last dose. Anyone taking prescribed methadone correctly tests positive. A positive result shows that a substance is in the body; it is not a diagnosis and says nothing about dependence, the amount or the time of use.
Negative
A negative result means no EDDP was found above the cut-off. In someone who receives prescribed methadone, this can mean the methadone was not taken in the last few days, but also that the urine was diluted or the dose is low. Heroin, morphine and other opiates are not detected with this test, and a standard opiate test in turn does not detect methadone.
If your result is abnormal
With a result that may have consequences, the laboratory has the result confirmed with a second method of analysis. The GP or addiction physician compares the result with the prescribed dose and the symptoms, and adjusts the treatment if needed.
Reliability
The test says something about intake of methadone in the past few days, not about the amount or about health. In addiction care, EDDP is used to check whether prescribed methadone is being taken. The Dutch Society for Clinical Chemistry (NVKC) states that a positive result of a screening test must be confirmed with a second, different method of analysis; a confirmation test is not included in this test.
Limitations
- A screening test can give a false-positive result; confirmation with a different method is needed before a result can carry weight.
- How long EDDP is detectable differs greatly per person, because the breakdown of methadone differs greatly per person.
- Methadone that has only been added to the urine does not produce EDDP and therefore gives a negative result.
- Fluid intake determines how concentrated the urine is; diluted urine can give a negative result.
How common is this
In 2024, 0.3 percent of adults in the Netherlands had ever used methadone. Methadone is mainly prescribed in addiction care, to a small and often older group of people who are or were addicted to heroin.
Who is this useful for
Useful for a medical question, mainly in addiction care to see whether prescribed methadone is being taken, or when use without a prescription is suspected. In people without such a question, the result adds little.
Downsides and risks
- A negative result due to diluted urine can wrongly be read as not taking prescribed methadone.
- A result without a confirmation test can wrongly be used as evidence.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results