What is a chain of custody and its importance?

• A. A documented record of sample possession from collection to analysis to prevent tampering and ensure data credibility
• B. A log of sampling teams
• C. A chart of sample volumes
• D. A summary report

Answer: (A)

Chain of custody is the documented history of who has possession of a sample and under what conditions from collection to analysis. This record includes who handled the sample, when and where transfers occurred, storage conditions, and any tamper-evident controls. It’s essential because it prevents tampering, preserves the sample’s integrity, and provides traceability for every step, which in turn supports the credibility of the data and matters for any potential review or legal admissibility. The best description is a documented record of sample possession from collection to analysis to prevent tampering and ensure data credibility. Other options describe only partial aspects or outputs—like who collected the sample, the volumes, or a general results report—and don’t capture the full controlled history that protects sample integrity.