Chain of Custody in Drug Testing: Ensuring Accuracy Every Step of the Way

Chain of Custody in Drug Testing: Ensuring Accuracy Every Step of the Way

Written by Amer Sheikh
October 29, 2023

Ever heard of "Chain of Custody" tests and wondered what it means? Let's break it down!


What is Chain of Custody?

Chain of custody refers to the chronological documentation of the handling, storage, and transportation of samples or evidence. It's a critical process that ensures the integrity of the sample from the moment it's collected until the time it's analysed, ensuring that no tampering, substitution, or contamination has occurred.

What does that mean? Imagine you're playing a game of "Pass the Parcel." Every time the parcel moves from one person to another, it's like passing a sample in real life. The "Chain of Custody" is like a rulebook that ensures the parcel (or sample) is passed correctly without any cheating or mix-ups.

Importance of Chain of Custody

The chain of custody is pivotal because it:

  • It makes sure the sample hasn't been tampered with.
  • It helps in getting reliable results.
  • If used in court, it ensures the evidence is valid.

Chain of Custody Example:

Let's say you're taking a drug test for a new job. You give a urine sample. This sample is carefully labelled, packed, and recorded. It then goes to a lab for testing. Every step is noted down to make sure no mix-ups or mistakes happen.

Chain of Custody in Drug Testing

When you hear about drug tests, chain of custody plays a big role. It's like a safety net that makes sure everything goes smoothly and accurately. Whether it's for employment, legal, or medical reasons, ensuring the sample's integrity is essential for accurate results.

Procedures for Urine Drug Testing

Steps for a Typical Urine Drug Test:

  1. You give a urine sample in a private space.
  2. Your sample gets a special label with your details.
  3. The container is sealed and documented on a chain of custody form.
  4. The sample is transported to a lab for testing.
  5. At the lab, the sample is analysed, and the results are documented.
  6. Any handover or storage is documented all through this process to maintain the 'chain'.

Chain of Custody in the Medical Field

Beyond drug testing, the medical field uses chain of custody for samples like biopsies, blood tests, and more. It ensures that patient samples are not mixed up, lost, or contaminated, guaranteeing accurate diagnoses and treatments.

Chain of Custody Forms

The chain of custody form is a crucial document that chronicles every step in the process. Think of it as a diary that notes down every step about the sample. Who gave it, where it was stored, when it was tested – everything!

Tests that Require Chain of Custody

While drug tests are common, other tests requiring a chain of custody include:

  • Forensic samples (e.g., DNA, fingerprints).
  • Medical tests (e.g., biopsies).
  • Environmental samples (e.g., soil, water).

Chain of Custody Guidelines

  • Some general guidelines include:
  • Always label and seal samples.
  • Document every step diligently.
  • Store samples in secure, appropriate conditions.
  • Limit the handling of samples to trained professionals.

Finding a Chain of Custody Drug Testing Location Near You

Several labs and testing centres offer chain of custody drug testing. A quick online search with the terms "chain of custody drug test near me" should provide local options. At Drug Test London we currently do Chain of Custody Urine Drug & Alcohol Testing.


In short:

Understanding the chain of custody is essential for anyone involved in sample collection, transportation, or analysis. It's like a safety rulebook for samples, and makes sure that everything is done right. It ensures the integrity of the sample, leading to trustworthy results, be it for legal, medical, or employment purposes. It's important to ensure that the chain remains unbroken for the most accurate outcomes.

Collection list

Alcohol Tests
Alcohol Tests

Alcohol Tests

Drug Tests
Drug Test

Drug Tests

Chain of Custody Drug Tests
chain of custody drug test

Chain of Custody Drug Tests

Postal Tests
home drug test kit

Postal Tests