Forensic DNA & Drug Testing: How it works

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Forensic DNA & Drug Testing: How it works

We’ve seen it on our favourite crime scene investigation TV shows and we’ve heard it solve age-old crime mysteries in the news, but the reality of forensic DNA and drug testing is slightly less dramatic than Hollywood makes out. The real-world applications of forensics and drug testing are numerous and include the legal sector, HR & recruitment, private clients, court cases, criminal cases, driving offences and more. 

In this article, we will address many of the key aspects of forensic DNA and drug testing, starting with...

What should you look for in a Forensic DNA testing company?

Of course, you should look for the same traits in a DNA testing company that you’d look for in any other company, such as trust, experience, high levels of service, and quality customer care. Superior testing companies will go above and beyond in:

  • Providing expert advice to testees throughout the process
  • Investing in technological advances to get the most detailed results for customers
  • Being understanding and sympathetic to the fact that DNA testing outcomes are often life-changing
  • Having great coverage and connected facilities (DNA legal offers 170 sites in 34 countries)
  • Customer support for evidence review, testing, and expert witness services
  • A dedicated case manager and forensic scientist to answer any questions you have and ensure a quick turnaround.
  • Our laboratory is Home Office Accredited to produce paternity testing.

We offer all of this and more, take a look at our forensic testing service page

What are the different types of forensic DNA tests?

We offer many different types of forensic tests, with some of the most popular including:

  • 21-46 STR markers
  • Y-STR
  • mtDNA
  • X-STR
  • SNP
  • Next-gen sequencing (including LCN reports)
  • Disaster victim DNA identification services

How does family and forensic DNA and drug testing work?

Different forms of DNA specimens can be tested. One of the well-known types is the DNA test that is performed by taking a buccal swab, which is a way to collect cells containing the DNA from the inside of a person’s cheek. Once collected, the samples get sent to a laboratory where a scientist extracts DNA and certain enzymes, primers and free DNA nucleotides are used to copy the genetic code and amplify the DNA quantity for better results. The Short Tandem Repeat (STR) test looks for markers in the sample’s DNA molecule, and it is within this sample that the markers vary massively between people who are unrelated but appear notably similar when people are related.

Scientists and Analysts use incredibly precise and complex software to assign a designation to the DNA markers. With multiple tests taking place to discover and confirm important information, the DNA profiles are eventually built and assessed for quality. Once a DNA profile is complete, it can be compared with the DNA profile of another individual and the significant markers can be tested for population and frequency to test if there is a biological relationship. An experienced analyst will then prepare a final DNA report for the relevant party.

What is the Expert Witness Service?

The legal world is a minefield for those who don’t understand it, which is why we set up our Expert Witness Service to provide an additional level of support to our valued customers. This service includes:

  • Defence Casework Review - Assessing the integrity and validity of your evidence and the results providing in scientific results
  • Expert reports for DNA and Toxicology - See here
  • Support with various offences and evidence types - firearm discharge residue, blood pattern analysis, marks and impressions, DNA transfer, and glass analysis
  • Independent expert consultation

What is toxicology in relation to drug testing?

Toxicology is the science of the measurement and analysis of potential toxins, intoxicating or banned substances, and prescription medicine present in the human body. It aligns perfectly within the legal and professional need for drug testing.

Here are some of the most common applications of toxicology reporting:

  • Hair testing for drug and alcohol use - Drug abuse, alcohol abuse, prescription medicine abuse, steroids and doping, and use of medication
  • Urine drug and alcohol for monitoring consumption any consumption or abuse behaviour
  • Toxicology investigations - hair, urine, blood, saliva, nails, gastric content, organs’ tissues and putrefactive liquid can all be tested
  • Blood alcohol or drug concentration - typically used for motor incidents

What can you learn from drug testing and analysis?

Toxicology for drug testing can reveal a great deal about what a person has consumed, but another type of drug testing can be applied to find out the identity (and purity) of unknown substances such as unknown substance, suspicious paraphernalia, powders, liquid, and pills. This drug analysis can also be used to detect traces of a drug have been present on objects like phones, clothes, money, or wrappers.

How is legal compliance and integrity maintained in the testing process?

It is with absolute care and compliance that we perform all of our services so that they are not only accurate and give peace of mind, but so that they can be used to provide justice in a court of law. Results can be the difference between life and death.

Here’s how we do it:

  • Independent sampling - We use an independent party who is unrelated to the sample giver or the case itself to take the sample. This is typically a medical practitioner or a trained tester.
  • Consent - The Human Tissue Act of 2004 requires us to get consent for any biological samples taken and tested. This is applicable for adults and children, and if an adult is caught committing DNA theft they can be jailed for up to 3 years or fined up to £3,000. Written consent for children must be made.
  • Chain of custody - This is vitally important for all forensics, DNA, drug testing and more. A chain of custody of the DNA samples must be kept and maintained to ensure the integrity and the lack of opportunity for tampering for interference.


We are the UK’s leading forensic testing services and expert witness provider because we have taken all of the necessary measures mentioned in this article. We have invested in the best technology, the best analysts, the best services, and all of those are designed to provide a superior experience for our much-valued clients.

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