Natalie Davies and Dr. Amira Guirguis discuss the scope of the first Home Office-licensed drug checking intervention, set inside a community substance misuse service in Somerset.

SSA: In 2020, you published a paper in Behavioral Sciences about the UK’s first Home Office-licensed drug checking service. This was a service that allowed people to submit a sample of their illicit drugs for onsite testing, after which they would receive harm reduction and treatment advice based on the results of these tests. Can you walk us through what the service would have looked like from the point of view of the service users?

Dr. Guirguis: “It was based in a substance misuse service in a beautiful area in north Somerset. We looked for a clinic that had a limited number of people in treatment so we could maintain control and see how it’s going to work. People were recruited through word of mouth, including through the staff in the clinic. We collaborated with the local police to make sure that service users didn’t get arrested when they had drugs on them, and they were really co-operative with us because they were really looking at harm reduction not at arresting people.”

“When people came they signed a consent form, and handed over their sample of drugs. I led the team who were analysing the substances, maintaining controlled drug registers, weighing the samples before and after, and in some cases manipulating the samples. It was quite hectic, because we had to analyse everything on the spot and somebody was waiting for the results. And when we got the results we had to carry out a multi-disciplinary briefing, where we shared the information from a legal, from an ethical, and from a clinical aspect; we covered all of this and then we formulated an intervention that we all agreed on, which was delivered after that by a specialist pharmacist colleague, Rosalind Gittins, who used to work for the substance use charity Addaction.”

“If service users decided that they want to go into treatment, or if they were already in treatment and they wanted their case worker to be present, they were allowed to do that. And that was even better because that would mean that their treatment would incorporate the data from the drug checking intervention.”

You used a single method of forensic analysis to test illicit drugs in this intervention – handheld Raman spectroscopy. In contrast, a festival-based intervention in the UK involved up to three different methods of analysis, and one in various community settings used up to six different methods of analysis. Was the decision to use just one method, in essence, limiting the drug checking by design?

“It was to some extent by design. It was purposely done that way for many reasons. The technique itself was from my PhD work and my research, so the equipment that we used was not the standard machine or instrument that you would buy from a provider. What we did was supplement that equipment with a very large library; probably the largest library of novel psychoactive substances in Europe. We also supplemented this work with algorithms, that have the ability to identify up to six components in the same mixture, and if the drug itself could not be identified, we could say it may belong to a certain class. We used only one technique on purpose because we wanted to test the technique that we developed, and we wanted to see whether that particular instrument is able to identify a wider range than current techniques.”

“The technique that we used is actually able to look at even a couple of particles of the powder. Many of the other techniques require a lot of sample in order to get a result. We didn’t want to put the service users off. We wanted to take as little as possible to do the analysis. Some people, for example, handed in samples that had already been consumed, and they found like very little dust or a couple of particles in paper or in a piece of carton. The Raman actually did a very good job with that. It wasn’t easy. It was extremely challenging, but it required some experience to be able to do such work.”

“The other point is that the technique is non-destructive, which means that if it doesn’t identify anything, I still have the sample intact, because literally I was analysing the samples through packaging, or through cling film, or in a plastic bag, or in a glass vial. So I did not destroy the sample. The sample was still there at the end, which meant that I could take the sample for further analysis in the lab. But if I put it, let’s say, in a colour test, it’s gone and I don’t have the sample to test further.”

Your paper indicated that handheld Raman spectroscopy was more successful at identifying the components of some substances than others. So for example, if there were very complex mixtures, it was difficult to determine what was in there. I wonder whether you would be able to give some examples of what kinds of things you could tell a service user about their drugs, and what you couldn’t?

“With the Raman in particular it is extremely successful when it comes to, for example, white powders. It’s very good with solids. It’s very good with pure substances. It’s very good with light colours. It’s not very good with mixtures with dark colours. It is good with liquid formulations, but it depends on the concentration of the drug, so if the concentration is poor it’s not going to detect anything. But that applies to most techniques as well. With infrared, which is a technique used previously in music festivals, you need quite a lot of drug in order to be able to detect it, but it is a very good technique. It is a better technique when it comes to coloured samples. The other one that actually most techniques don’t detect are the herbs. Most of the herbs contain hundreds of phytochemicals, and lead to signal interferences, so you will get a very complex signal and you will not be able to identify the drugs.”

“The way the Raman works basically is by shining a laser on the matter. From that you get scattered light. If the scattered photons have a different energy from the absorbed energy, you get a signal of the different wavelengths (Raman shifts), and that presents a fingerprint of the actual compound. The laser light beam diameter is in the micrometers, or nanometers. So, it’s very easy to miss an active substance in the sample. It’s way smaller than one particle. Fentanyl, for example, is usually present in mixtures in minute amounts. You may not have enough fentanyl in your sample, and if that’s the case, you may completely miss it.”

Did you find that this intervention was able to facilitate more tailored harm reduction conversations than if service users had self-reported their drug use?

“Yes, so, I think the purpose of the intervention was bringing people into treatment. And I think that was one of the successes of this clinic; is it has attracted those types of people who were not in treatment at all or didn’t even know about the different harm reduction interventions that are available, for example like vaccinations.”

“When they came to the clinic they completed a questionnaire so we knew whether they had any co-morbidities, if they were taking any other drugs (whether prescribed or non-prescribed). Also, there were a number of healthcare professionals with different types of expertise contributing to the formulation of that final intervention. Basically we quickly tell, okay this is what the analysis says, this is the information we have about the patient, how can we marry the two together to ensure that the patient is not going to be harmed, and we basically tried to see if they would be willing to come into treatment. And that made it a multifaceted intervention for that particular patient, so it was very tailored.”

In the paper you used the term ‘drug checking’ – as opposed to ‘drug safety testing’, which has been used elsewhere in the UK to describe onsite testing and harm reduction interventions in festivals and community settings. Can you tell us what (if anything) distinguishes one from the other?

“Drug checking was the preferred term and the one we were advised to use by the Home Office when we had the licence. ‘Checking’ implies that we are only screening; we’re not confirming the content. So, I may completely miss the drug if the drug is present in only a very small amount in a tablet. Illicit drugs are not produced according to pharmaceutical standards, so the active ingredient may not be uniformly distributed in a tablet. Let’s say you have a tablet, and the tablet contains a lot of ingredients, fillers, binders, and excipients, but you take the measurement from a point when you have no drugs – you may completely miss the drug. And you may think, ‘okay, it doesn’t have any drugs in there, it only has lactose or microcrystalline cellulose’. So therefore checking was basically describing it as accurately as possible, but there was a very high possibility of actually having a false negative in terms of the drug content.”

“If we used the term drug safety testing instead, the wording may be slightly misleading, because we are not really providing any safety testing. We’re not really saying that after the analysis, ‘this is safe or unsafe’. We can’t say it’s safe at all, because there is no safe drug to take, and there is no safe way to take it. So I guess that was the message.”

What’s next for this intervention?

“We were actually planning a much larger study but unfortunately things have stopped because of COVID-19. Next for us is to publish the final paper, where we will analyse how we performed and how we can improve the in-field detection quality of the technique moving forward.”

Dr. Amira Guirguis is a Senior Lecturer in Biomedical Sciences at Swansea University, and was the Principal Investigator of the first-Home Office-licensed, pharmacist-led drug checking service in the UK.

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