How to detect admin is logged in

I’m using MODx as the main content for a site, but it also includes some external PHP apps. As I’m using MODx for user login, I need to be able to detect - from the external app - when someone is logged in as an admin. I’m searching on this, but if someone can help point me in the right direction, I’d be grateful as I’ve no idea how MODx does user verification.

Here is a tutorial for loading the MODx api into an external app, once the api is loaded you can use the api methods to see who is logged in. http://wiki.modxcms.com/index.php/MODx_site_menu_in_external_PHP_app

Here is a recent discussion on the subject that could give you some ideas: http://modxcms.com/forums/index.php/topic,24701.0/topicseen.html