Chain of custody in laboratory testing: why it matters

Chain of custody (CoC) is the documented record of who collected a sample, how it was stored and transported, when it arrived at the laboratory, and how it was handled through the analytical process. For most routine testing, it runs in the background without anyone thinking about it. For results that will be used in a legal dispute, a regulatory submission, or a property transaction, it becomes the thing that determines whether the result is accepted or challenged.

What a chain-of-custody record contains ¶

A complete CoC record starts at the point of collection. It includes the date, time, and location of sampling; the name of the person who collected the sample; the container type and any preservatives used; the temperature at collection and during transport; and the time of arrival at the laboratory. At the lab, the record continues with the sample log-in, the analyst assigned, the method used, and the instrument and calibration records for the equipment involved.

At Lank CoreLab, every sample is photographed on arrival and assigned a unique reference number that appears on all documentation through to the final report. The CoC documentation is included with the report as standard.

When CoC documentation is legally significant ¶

In a legal dispute, the opposing party's first line of attack on an analytical result is often the integrity of the sample. If the CoC record has gaps, if the sample was not kept at the correct temperature, or if the transit time exceeded the holding time for the parameter being tested, the result can be challenged regardless of how well the analysis was performed.

Environmental enforcement cases, planning appeals, and insurance claims all commonly involve analytical results. If there is any possibility that your results will be used in a formal process, it is worth discussing the CoC requirements with the lab before you collect the sample, not after.

Practical steps for maintaining CoC before the sample reaches the lab ¶

The lab can only document what happens once the sample arrives. What happens before that is your responsibility. Use the containers and preservatives specified by the lab for the parameter you are testing. Seal and label the sample immediately after collection. Keep it at the specified temperature during transport. Note the time of collection and the time of dispatch.

If you are collecting samples for a legal matter, consider having a second person present as a witness to the collection, and photograph the sample location before and after collection. These steps take a few minutes and can make a significant difference if the result is later disputed.

• Use lab-specified containers and preservatives
• Seal and label immediately after collection
• Maintain specified temperature during transport
• Record collection time and dispatch time
• Photograph the sample location

If you are preparing for a submission where the CoC record will be scrutinised, it is worth a five-minute call with us before you collect. Getting the documentation right from the start is considerably easier than trying to reconstruct it afterwards.