Metals, toxins and medication
Morfine
A urine test for opiates shows whether morphine, codeine or a related substance was in the body recently.
Everything about this testWhat it measures
The analysis looks for opiates as a group in urine: morphine, codeine and related substances. You receive one result for the whole group, not a separate value for each substance. Morphine is a strong painkiller that is also prescribed as a medicine. In addition, morphine is formed in the body from heroin and from codeine. Heroin use therefore also gives a positive result, but the test cannot tell heroin apart from morphine or codeine; it looks at a group of substances and not at one source.
- The presence of morphine or related opiates in the urine, after use of morphine as a medicine, of codeine or of heroin
Positive
A positive result means that there is morphine or a related substance in the urine above the laboratory's limit. According to the Dutch Society for Clinical Chemistry (NVKC), opiates can be detected about 2 to 3 days after use; the Trimbos Institute gives 2 to 4 days for heroin. There are more explanations than drug use: morphine and codeine as medicines, oxycodone and hydromorphone, the drug ranitidine and eating poppy seeds can give a positive result or a cross-reaction. 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 that no morphine or related substance was found above the laboratory's limit. This does not completely rule out use: after a few days the substance has disappeared, and very shortly after use the result can still be negative. Diluted urine from drinking a lot can bring the value below the limit.
Preparation
- Do not eat poppy seeds in the 3 days before collecting, not even on bread or in pastries. Poppy seeds can give a positive result.
If your result is abnormal
With a positive result that may have consequences, confirmation is needed with a second analysis method that can distinguish morphine, codeine and other opiates from each other; this is done in blood. The GP then goes over the medicines and food of the past few days.
Reliability
An opiate test in urine shows that morphine or a related substance was present, but not where it came from. The Dutch Society for Clinical Chemistry (NVKC) writes that a positive result of a screening test must be confirmed with a second, different analysis method. Without knowing which medicines someone takes and what someone has eaten, a positive result cannot be interpreted.
Limitations
- Poppy seeds, for example on bread or in pastries, can give a positive result without any drugs having been used.
- Prescribed medicines such as morphine, codeine, oxycodone and hydromorphone give a positive result.
- A screening test can give cross-reactions; confirmation with another method is needed before a result can carry much weight.
- Fluid intake determines how concentrated the urine is; diluted urine can give a negative result.
How common is this
Heroin use is uncommon in the Netherlands and mainly concerns a small, often older group of long-term users. Morphine and related opiates are, in addition, much more often prescribed as painkillers, for example after surgery or for severe pain.
Who is this useful for
Useful for a medical question from a treating doctor, for example in addiction care, in pain treatment with opiates or when poisoning is suspected. In people without such a question, the result adds little. A result can only be assessed if it is known which medicines someone takes.
Downsides and risks
- Poppy seeds or a prescribed painkiller can lead to a positive result that is wrongly read as drug use.
- A result without a confirmation test can have major consequences that are out of proportion to the certainty of the test.
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