How can I convert an 8 character Hex word to binary for a lookup?

I have a machine that spits out a string of 8 Hex characters that I need to
provide a lookup table to identify conditions. Since the positive limit of
Hex2bin is 1FF, I need to isolate one or 2 nibbles for translation.

E.G.: How can I pick out something like the FF in a string of 01a4FF92?