Quality assurance (QA)

Quality assurance is the system of planned procedures, oversight and documentation designed to ensure that a manufacturing process consistently produces what it is meant to.

Where quality control tests the product, quality assurance governs the process: approving suppliers, writing and enforcing standard operating procedures, training staff, reviewing batch records and investigating deviations. It is preventive by design, aiming to stop errors before a batch is made rather than catching them afterward. In regulated manufacturing it is typically a separate function with authority to release or reject batches.

For a reader, the visible traces of quality assurance are indirect: consistent batch numbering, a certificate of analysis for every lot, best-by dates supported by stability data, and prompt handling of problems. A company describing itself as following good manufacturing practice is describing a quality assurance system. None of this replaces reading the certificate for the batch in hand, but it explains why one company's certificates arrive reliably and another's do not.