The Quality audit is the process of systematic examination of a quality system conducted by an internal or external quality auditor or an audit team. The audit is important part of organization's quality management system and is a key element in the ISO quality system standard, ISO 9001.

Internal audits will help you focus your ISO 9001 quality audits on "opportunity identification" rather than on "catching people".
An ISO quality audit is a management tool used to evaluate, confirm, or verify activities related to quality. ISO 9001 quality audits are the most common ISO standard for audits, but audits for all ISO standards can be done.
Benefits of an ISO 9001 Quality Audit
Quality audits can be extremely beneficial - when done correctly. They help you "find and fix" problems during implementation. An ISO 9001 quality audit is one of the most effective tools in the ISO 9001 toolkit for ensuring a certain level of discipline in performance as well as driving long term continuous improvement.
ISO 9001 Quality Audit Categories
System Audit - looks at a particular system which includes multiple processes and can spread across several employees and departments. The audit of your calibration system can be considered a system audit. Your process interaction document identifies your systems.
Conformance Audit - an audit to define system requirements. These are global in nature. For example a 3rd party audit of your ISO 9001 system is a conformance audit.
Compliance Audit - an audit to regulatory requirements. This includes government agency audits.
Process Audit - a focused audit on a set of processes within your organization. It examines adherence to procedures and specifications during production or service activities.
Product Audit - a focused audit on the product itself. This is typically an inspection activity.
Department Audit - a focus audit on one department that looks at the processes, specifications, and systems in one department only. It will look at the different operations with in that department. It will also examine department organization and training. The purchasing or design departments can be typical department audits.