I realize that I could just do a conversion to determine the pin's state, but I need to sit in a loop and look for a really short toggle.

The reason I have to configure it as analog is that the signal is connected to AN1, and I need to configure AN2 & AN3 as analog. The circuit is already built and I can't change the wiring.

I think the best solution is to do what Melanie suggested and configure the port as digital, read the pin, convert to analog, read channels 2&3, and switch back to digital.