The patch level of a system indicates which security updates and software patches have been installed and which are still outstanding. A current patch level means all available patches have been applied. In your vulnerability management, the patch level is a key metric: it shows at a glance which systems are vulnerable. Many organizations track patch levels automatically through endpoint management or vulnerability scanners. With NAC systems, an outdated patch level can result in a device being moved to a quarantine VLAN. Document patch levels regularly, as auditors frequently ask about them.