Choosing an analytical laboratory

Sound science relies on sound lab results. In choosing an analytical lab it is important to consider the status of its accreditation, which methods are accredited, and what quality control, holding times, and proper dangerous waste disposals are in place.

Check accreditation status for specific methods

 A rack of glass bottles with stoppers sits on a counter near a flask-mixing unit. A blue-gloved hand adds a purple substance to the mixture in the flask on the unit.

Accreditation is the best indicator that a lab has the capability to do a good job. While it is not proof of the quality of all of their data, it means that the lab is capable of providing accurate, representative, comparable, complete, and defensible data. If any analysis is not performed in-house, all supporting labs should be accredited, as well.

If you need a lab to use a specific analytical method due to legal mandates or grant requirements, for example, make certain that the lab is accredited for the specific method you need. Check our Lab Search database to find which labs are accredited for a specific analytical method or to list the specific analytical methods for any accredited lab.

Call the lab to confirm the methods they use in their reports. The lab may be accredited for an alternate method, but that will not help if you are required to use a specified one. If you have trouble finding an accredited lab for a specific method, you can contact us.

See quality control tests

Expect the lab to report the results of quality-control tests, such as blank, standard, and duplicate samples, at no extra cost. Check both precision and bias estimates to judge whether or not the lab is likely to have done accurate work. Ask for results of quality-control tests done with the batch in which your samples were analyzed. If there are any questions concerning interpretation of the control results, contact us.

Know that they meet holding-time requirements

Labs must be able to meet holding-time requirements for samples. Accreditation certifies that the lab is able to meet holding times, but it does not mean that this is true for your sample. Most labs provide a form to record the time a sample was taken and by whom. When the sample is delivered to the lab, the person receiving the sample should sign your form and return a copy showing the date and time the sample was received by the lab. The lab’s report back to you should show when the sample was extracted, if an organic analysis is being done, and when it was analyzed. This establishes that holding times were met and is essential in case the data is legally challenged.

They must manage dangerous waste properly

Laboratories must properly manage dangerous waste. To avoid mismanagement of your samples by the laboratory, ask the lab to certify that it will dispose of the samples according to existing regulations or return the samples to you for proper disposal.