Chain of custody explained: why it makes a result defensible
Two samples can be analysed by the same laboratory, with the same method, and produce the same finding — yet only one may be relied on. The difference is not the analysis. It is the chain of custody.
The principle
A result is only as strong as its story
When a result is challenged — in court, at tribunal, in a care hearing — the challenge is often to the story around it: was that really the donor’s sample? Could it have been swapped, contaminated or interfered with? Who handled it, and when? Chain of custody is the documented answer to every one of those questions, recorded contemporaneously at every step, so the story is harder to pick apart later.
The links in the chain
- Identity. The donor’s photographic ID is checked and recorded at collection. The sample is connected to a person, not an assumption.
- Witnessed collection. A trained collector follows a defined procedure, records the details, and observes the requirements appropriate to the sample type.
- Unique identifiers, not names. The sample travels under a unique reference. Laboratory analysts work to the reference, not the name — protecting both privacy and objectivity.
- Tamper-evident sealing. Samples are sealed in front of the donor, who confirms the seal. Interference is visible, recordable and reportable.
- Documented hand-offs. Every transfer we handle is recorded. In transit the sample is protected by tamper-evident seals and tracked delivery, and the laboratory checks the seals on receipt.
- Accredited analysis. Analysis takes place in an ISO 17025 accredited laboratory, under the quality system that accreditation requires.
Why home kits fall short
A home test kit may use respectable chemistry, but it cannot answer the questions that matter: whose sample was it, and what happened to it before the result? No identity check, no witness, no seal, no documented journey. That is why home kit results are not suitable for court-directed or official testing — and why NIVHA offers chain-of-custody collection only, with no home kits. The same standard applies whether the instruction is a court case or a workplace programme, because a workplace result may face the same scrutiny at tribunal.
What this looks like for the donor
For the person being tested, chain of custody is straightforward: bring photographic ID, expect the process to be explained, watch your sample being sealed, and sign to confirm it. It is designed to protect the donor as much as the instructing party — an intact chain is also the donor’s protection against a mix-up. What to expect on the day is covered at attending a test.
Chain of custody in DNA testing
In DNA cases the chain carries extra weight, because the result decides relationships with legal consequences — parentage, inheritance, immigration. Requirements are stricter: identity documents and photographs for every person sampled, an approved witness where required, and reporting prepared for use in proceedings. This is what separates a legal DNA test from an over-the-counter ancestry kit.
Common questions
Chain of custody — your questions answered
What does chain of custody actually mean?
It is the documented, unbroken record of a sample’s journey — who collected it, from whom, when, how it was sealed, and every hand it passed through on the way to the laboratory. If any link in that chain is missing, the result is open to challenge; if the chain is intact, one of the main grounds for challenge is removed.
Why are home test kits not suitable for court?
Because nothing connects the result to the person. With a home kit there is no identity check, no witnessed collection, no tamper-evident seal and no documented journey to a laboratory — so there is no way of knowing whose sample it was or what happened to it. Chain of custody is precisely what fills that gap.
How is the donor’s identity confirmed?
Photographic ID is checked at collection and the donor confirms the sample is theirs as part of the documented process. In DNA cases the requirements are stricter again, with identity documents and photographs recorded for every person sampled.
What stops a sample being tampered with?
Samples are sealed in the donor’s presence with tamper-evident seals, usually signed or initialled by the donor. Any interference with the seal is visible on arrival at the laboratory and would be recorded and reported.
Does chain of custody apply to workplace testing too?
Yes. Any result that might support a disciplinary decision should be collected to the same standard as a court sample, because it may need to survive the same level of challenge — at tribunal rather than in court. NIVHA applies one professional standard to every collection.
Need a result that will stand up?
Every NIVHA collection follows full chain of custody as standard. Get a quote for court work, or talk to us about your case.
This page is a general guide. It is not legal, medical or technical advice. Laws, guidance and laboratory methods change, so check the current requirements for your own case. Last reviewed .