What are the types of hearing screening required for newborns?

Many states now require newborns to have their hearing tested prior to discharge from the well baby nursery.  One of two tests can be done.  The first an otoacustic emission test which evaluates the sounds our ears make when they hear an external sound.  The second test is a brainstem evoked potential which is looking at the electronic brain waves produced as the ear and then brain "hears" a sound.  The emission test is quicker and easier to do but has a fair number of false failures that require retesting to be sure the baby hears.