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Legal DNA testing: The chain of custody explained

by | Jul 3, 2026 | Legal & Immigration

When DNA test results are needed for legal purposes, such as family court proceedings, immigration applications or probate matters, the testing process must meet strict standards. Unlike DNA tests completed for peace of mind purposes, legal DNA tests require a documented chain of custody to verify the identity of the people being tested and ensure that samples are collected, handled and analysed securely. In this blog, we’ve explained what the chain of custody is, why it matters, and how it helps ensure DNA test results are legally admissible.

What is the chain of custody?

The chain of custody is a documented record of the collection, handling and analysis of DNA samples. It provides a complete paper trail, demonstrating that a sample has remained secure, accounted for and free from tampering throughout every stage of the testing process.

For legal DNA testing, the chain of custody documents every transfer of the sample, from donor identity verification and collection through to transportation, laboratory analysis and reporting. This unbroken record provides confidence that the DNA evidence tested is the same sample originally collected.

Why is the chain of custody important?

Maintaining the chain of custody is one of the most important aspects of legal DNA testing. It governs every stage of the process, from sample collection and handling to secure transportation and laboratory analysis, helping to eliminate the risk of tampering, misidentification or procedural errors.

The chain of custody ensures:

  • Admissibility It helps ensure DNA test results can be accepted as legal evidence because the integrity of the sample can be demonstrated.
  • Authenticity – It confirms that the DNA sample analysed is the exact same sample that was collected and that it has not been altered or manipulated.
  • Accountability – It records every individual who has handled the sample throughout the process, providing full traceability and responsibility at every stage.

Legally admissible DNA testing with NorthGene™

NorthGene™ maintains a strict chain of custody from collection through to reporting for all legal and immigration DNA tests. As a UKAS accredited and Ministry of Justice approved laboratory, we follow rigorous procedures to ensure results are delivered accurately, securely and in accordance with the requirements for legal admissibility.

Our legal DNA testing services include:

  • Paternity
  • Non-invasive prenatal paternity
  • Maternity
  • Siblingship
  • Avuncular (aunt/uncle to niece/nephew)
  • Grandparentage

How does the chain of custody work?

Our meticulous chain of custody process provides confidence that every DNA sample submitted for legal testing is accurate, secure and suitable for legal proceedings.

  • Impartial sample collection – Samples for legal and immigration DNA testing are collected by an independent third-party sample collector. Our nationwide network of collectors is DBS checked and thoroughly trained in maintaining a compliant chain of custody. Each collector signs a legal declaration confirming that the samples were collected from the individuals named on the consent form on the stated date.
  • Identity verification – Every participant must provide valid photographic identification, such as a passport or driving licence, to verify their identity before samples are collected.
  • Photographic confirmation – The collector also takes a photograph of each participant and certifies that it is a true likeness of the individual who provided the sample.
  • Tamper-proof return – Samples are sealed immediately in tamper-evident packaging before being returned securely to the NorthGene™ laboratory. On receipt, every package is checked for signs of tampering before testing begins.
  • Confidential reporting – Results are released only to the authorised individuals named on the registration form, typically the instructing solicitor, ensuring the highest standards of confidentiality and data protection. Identity verification records are also provided alongside the report as supporting evidence of the chain of custody.

Why choose NorthGene™ for legal DNA testing?

Whether you need DNA testing for family court proceedings, immigration, probate or another legal matter, choosing an accredited laboratory with a robust chain of custody process is essential.

At NorthGene™, our experienced team is here to guide you through every stage of the process, from arranging sample collection to delivering accurate, legally admissible results. Contact us today to discuss your requirements or learn more about our legal DNA testing services.

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