Which test requires a chain of custody?

A chain of custody is crucial in situations where the integrity and provenance of a sample must be maintained, ensuring that it can be accurately traced from collection through to analysis and eventual reporting. In the context of drug testing, the chain of custody procedures are vital because they help prevent tampering, contamination, or mislabeling of samples. This is particularly important in legal or workplace scenarios where the results of drug tests could have significant implications for individuals.

The process involves meticulous documentation at every stage, from when the sample is collected to when it is analyzed in the lab. It includes maintaining secure transport and storage conditions and having proper records of all personnel who handle the sample. In contrast, other tests like complete blood count, blood glucose testing, and hematocrit measurement do not typically involve the same level of legal scrutiny or need for strict procedural safeguards regarding handling and transport. These tests are primarily used for clinical evaluations rather than legal or regulatory compliance, which is why they do not require a formal chain of custody.