What Is an Audit Trail? (GxP)

In a GxP context, an audit trail is a secure, computer-generated, time-stamped record that captures who created, modified, or deleted an electronic record, and when. It's one of the core expectations under 21 CFR Part 11 and the broader ALCOA+ data-integrity principles (Attributable, Legible, Contemporaneous, Original, Accurate — plus Complete, Consistent, Enduring, Available).

The bar an inspector actually cares about isn't just "does a log exist" — it's whether that log can itself be tampered with. A log table that an administrator can quietly edit or delete rows from isn't really an audit trail; it's a log with an asterisk.

A stronger version of this is a hash-chained, append-only design: every entry is cryptographically linked to the one before it, so an altered or deleted row breaks the chain and is detectable, and a database-level control blocks the edit/delete operation outright — including for elevated/admin credentials, not just ordinary application requests. That's a meaningfully different guarantee than "we log changes."