Statistical Bulletin 2023 — methods and definitions for syringe residues (ESCAPE)

This page provides methods and definitions information for Syringe residues data, which form part of the EMCDDA's Statistical Bulletin 2023.


While evidence from drug treatment centres suggests that injecting drug use is declining among heroin clients in the European Union, the risk of overdose death and infectious diseases associated with this mode of administration remains high. The injection of stimulants — including cocaine and synthetic cathinones — has been linked to increased risk of HIV and hepatitis C virus (HCV) transmission, through increased frequency of use and sharing of injecting paraphernalia. Knowledge of what substances are being injected is important to guide prevention strategies and plan the provision of harm reduction interventions.


ESCAPE — the European Syringe Collection and Analysis Project Enterprise — aims to identify the range of substances being used by people who inject drugs in a sentinel network of cities in the EU and neighbouring countries and to monitor changes in patterns of use over time. It provides city-level data that can complement other information and indicators on drug consumption and potential emerging health threats in the region.


The methods of the ESCAPE network are detailed in the ESCAPE generic protocol. Since 2017, study teams at the city level collect on a yearly basis a target of 150 used syringes from low-threshold harm reduction services. After appropriate extraction of their content, the samples are analysed in the participating laboratories, using either targeted or non-targeted screening methods. The primary indicator shown in the data explorer is the percentage of syringes testing positive, by drug category, by city, by year. The denominator is the number of syringes testing positive for at least one drug category. The drug categories are listed in the generic protocol. Other indicators of interest include the percentage of syringes containing 2 or more drug categories, and the most frequent combinations detected.

Main limitations

  • The results are based on a sample of syringes only, and reflect local specificities of the drug markets and sub-populations of users accessing the participating harm reduction services: they are not necessarily representative of the national situation.
  • The high proportion of syringes containing residues of stimulants could reflect a higher frequency of injecting among stimulant users than among non-stimulant users, rather than a higher prevalence of stimulant use than other drug use among people who inject drugs (selection bias).
  • Drugs found in syringes may originate from blood drawn into the syringe during an injection, that is, from drugs consumed prior to the injection, possibly through other modes of administration (measurement bias).
  • It is not possible to distinguish a syringe containing residues of multiple drugs that had been used once from a syringe that had been reused by one or several users.