How to do a hardware level check for Anisotropic filtering support?

I just finished implementing Anisotropic filtering support in my game, but I'm not quite sure how to do a hardware level check to see if the user hardware supports the method. Is there a way to use CheckDeviceFormat to see if the hardware supports it, or does the device automatically default to trilinear if the hardware doesn't support anisotropic filtering? Thanks in advance :)