Back to School Series – Part 1

Chain of Custody (COC) Form Essentials

COC’s are a critical component to maintaining the integrity of the sample and play a crucial role in communicating with analysts in the lab. Save time and money by understanding what’s important.

How is your memory? 

Do you remember what you were wearing on this day 4 years ago? How about what you ate for dinner? Or what the weather was like?

Quote 1Recalling information about your sampling event today years from now might be difficult as well, if not impossible. That’s why recording all necessary sampling information on your COC form at the time of sampling is important. If samples are called into question, referencing the COC is often the first place a data reviewer looks.

Proper documentation also helps improve data quality, and reduce costly mistakes that can lead to resampling. Let’s find out why.

Impact to Quality

Good data starts off with a good COC form. The COC form tells a story about your sample. It tells where samples came from, their age, who collected them, and what their testing needs are.

Quote 2In legal cases utilizing sample results as evidence, essential documents related to the sampling, including the COC, are called into question as the chronology and paper trail is established. The properly completed COC is an important component of that paper trail.

The COC is where you indicate specific analysis, methods, and target lists required for your sample. Some analyses consume most or all of the sample, and some analyses have short holding times, so adding additional tests after-the-fact may not be possible. Some analyses require specific preservatives, so running them out of a different container is not possible. It’s important to ensure this is clear.

The COC is also where any known characteristics of the sample should be noted. Are there likely high concentrations of a particular pollutant that would be helpful for analysts when determining dilutions? Does the sample contain hazardous material (e.g. asbestos) which would require additional safety precautions for our staff, or isolation when we store the samples? This information can be indicated on the COC.

If samples are being reported to a particular regulatory agency, data packages containing QA/QC information may be necessary. This will need to be discussed with your project manager and can be indicated on the COC form.

What Needs To Be Recorded

Once your sample is collected and labeled, be sure to record your COC form on-the-spot.

Field conditions can be rough at times. Our sampling team understands the challenges of collecting field samples in the rain, sleet and snow, but legible handwriting is a must. Contacting clients to confirm unreadable or missing dates, times, or analysis methods, for example, can delay the processing of your samples and cost your project valuable time.


Example Chain of Custody Form
Example Chain of Custody Form

Information that is essential:

  • your account name and related information
  • sample site, date and time collected
  • sampler initials
  • analysis required
  • matrix (soil, non-potable water, potable water, SDWA, etc.)
  • sample type (grab, composite)
  • the specific testing requested.

Rush turnaround time requests should also be noted, and, when possible, alert the lab to be sure the rush can be accommodated. We will do everything in our power to ensure you get results when you need them.

Upon arrival in our sample receiving department, all of the information on a COC is input into our LIMS (Laboratory Information Management System software). After receipt, information related to your samples as they travel through our laboratory are tracked, monitored and reported using our LIMS. Having everything correct at the start get’s your project off on the right foot.

At Suburban Testing Labs, we hold quality data first and foremost in our daily objectives. We want to ensure we provide you with data that ensures your project a successful outcome. If you have questions about filling out a COC, or would like to host an in-house training on recordkeeping with your team, please do not hesitate to contact us.


Contact Us!

We look forward to working with you on your next project! Contact us for information today.