How to check whether the application is in the center of the monitor?

I'm working on a project using Visual Studio, TestStack.White, and NUnit. I want to run a GUI test to make sure the application opens up at the center of the screen. So far I have tried finding an equivalent of Form.StartPosition (but I don't have an instance of the form, so something related to this in the Application or Window classes), used math and Window.Location, and I've also browsed through the entire Application and Window classes on MSDN to find a solution.

Thanks.