Hello,
The NAC Agent can check to see if an application is running (ie., the "Service State" check) and if you enable this particular test criteria, you can also configure it include "Auto Remediation" which means that it will stop or start the application, per how you configured the test. Due to that functionality I believe this equates to yes, the Agent can ensure that the application is running.
Does this answer your question?
Regards,
Scott Keene
Extreme GTAC