Forensic Toxicology

Fast identification and analysis of drugs

With over 30 years’ experience supporting criminal and death investigations, we offer a wide range of forensic toxicology services either as off-the-shelf or bespoke packages which utilise our extensive analytical and forensic expertise.

Our forensic toxicology team investigates and interprets the presence of alcohol, drugs and poisons in biological samples for coronial, civil and legal purposes. Our results are determined and quantified using liquid chromatography tandem mass spectrometry (LC-MS/MS) or liquid chromatography high resolution mass-spectrometry (LC-QTOF) with and are then fully interpretated with regards to the specific case circumstances.

Who do we work with?

We work with coroners, pathologists, analytical laboratories, solicitors and barristers and have established specific protocols and reporting formats to ensure that our service is precisely aligned with our clients’ requirements and the legal process, with full chain of custody in place.


Our work with coroners and pathologists is to establish whether the use of alcohol and drugs may have contributed to the cause of death through post-mortem body fluid and tissue analysis.

We assist in investigating sudden or unexplained deaths which can answer:

  • Could an overdose of alcohol or a drug have been taken?
  • Could the presence of multiple drugs, including alcohol, have caused toxicity?
  • What is the likelihood that the correct dose of prescribed medication taken by the deceased? This can include antidepressants, hypoglycaemics and anticonvulsants.

Other services are tailor-made to meet the needs of individual cases which can involve the analysis of various bodily fluids and tissue samples to determine minute traces of drugs and poisons, and sub-therapeutic levels of medicines. These findings are interpretated  using the specific case circumstances.

Police, Prosecution and Defence Solicitors

At ASI we undertake analysis of biological specimens for drugs and alcohol, to support police and solicitors dealing with a variety of allegations where alcohol or drugs may have contributed towards the circumstances of the case. These include, but are not limited to, drink and drug driving, drug facilitated sexual assault, murder, suspicious deaths, poisonings and assault.

Drink and drug driving cases may involve Sections 5 and 5A of the Road Traffic Act 1988 (driving or being in charge of a motor vehicle with alcohol or drugs exceeding a specified limit) investigations. We also assist in analysis for cases involving Section 4 of the Road Traffic Act 1988, namely driving or being in charge of a motor vehicle whilst impaired through alcohol or drugs.

Our forensic toxicologists can assist with:

  • Determining the presence of alcohol or drugs in blood or urine in cases of alleged drink/drugs driving, and measuring their concentrations if necessary.
  • Alcohol calculations to support whether the toxicological results obtained support a given narrative.
  • Providing expert evidence in courts of law.

Work pertaining to Sections 5 and 5A of the Road Traffic Act 1988 are UKAS accredited under ISO/IEC 17025:2017 and is undertaken in accordance with the Forensic Science Regulator’s Code of Practice and Conduct. Furthermore, alcohol related calculations such as alcohol technical defence cases are also encompassed in the scope of our accreditation.

Expert Witness

The experts at ASI are experienced at delivering an expert witness service, which includes incorporating all legally defensible results in an expert witness statement and attending court to provide testimony, if requested.

Contact our forensic toxicology experts to discuss the requirements of your case.


Contact Us

Our forensic toxicology laboratory is based at St George’s Hospital in London and is delivered across the UK.

Contact our team to discuss your case requirements.

UKAS Testing - ASI 7641

All our forensic toxicology is undertaken in accordance with the Forensic Science Regulator’s Code of Practice and Conduct.

Their excellent interpretation of results is very helpful.
Using an esoteric assay service saves us the time and money involved in setting up such screens.