The poppy seed defence: all you need to know 

Some food products such as seeded breads, bagels, muffins and cakes contain poppy seeds. Culinary poppy seeds are from the same family of plants as the opium poppy and all of these seeds contain small quantities of codeine and morphine. This means with consumption of these goods, donors may test non-negative for opiates but our expert team are trained to differentiate the two.

How can you tell if a result is due to poppy seeds rather than consumption of medications/drugs?

There are a few things we consider when interpreting opiate results at SYNLAB Laboratory Services:

• The level of codeine or morphine found in the sample.
• The ratio of codeine and morphine to each other in the sample.
• The presence or absence of other distinctive markers.

What are the other distinctive markers  and how do they help?

With every opiates sample we test, we check for the presence or absence of the following markers:

• Thebaine †
• Desmethylpapaverine †
• 6-MAM

† – unaccredited.

Thebaine is often seen at low levels in a urine analysis test where poppy seeds have been ingested. Thebaine is destroyed when heroin is made so we would not see it in a urine sample test whereas high levels are seen when somebody takes opium.

Desmethylpapaverine is only seen in test urine samples where opium or heroin is being used.

6-MAM is only seen in urine samples of donors who have used heroin or its pharmaceutically pure version, diamorphine.

What do we do if our policy is zero tolerance and we have a positive result that is consistent with poppy seeds?

We recommend that if you have doubts about the sample results, you conduct a further sample testing after seven  days avoidance of consumption of poppy seeds. You could also conduct an occupational health review if you feel it is necessary for the type of work the donor is involved in.

The report says the result “may be” due to poppy seeds. How can I be sure?

If we detect low levels of codeine and morphine and nothing else, then we can’t determine whether this is from undeclared medication or poppy seeds. We always take a cautious approach and will not report a “fail” unless we are sure. However, if we do only detect low levels (and the donor is not taking any other opiates) then it is unlikely that your employee is abusing opiates.

How many poppy seeds are needed to give a positive result?

Only a few grams are needed to give a positive result. In fact, just a few slices of multi-seeded bread can cause a positive result. Poppy seed bagels typically have just 3-5g poppy seeds per bagel and seeded bread may contain around 10g per loaf. Average poppy seed consumption in the UK is 5g per day.

For more information on our workplace drug and alcohol testing services, click here.

Published 11/06/24. All information correct at time of publication.

Written by Michelle Csete

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