Some (a relative few) schools have minimum GPA/MCAT cutoffs
Some schools have an auto secondary that goes out once you apply.
The rest like to enter you into their system or just wait until they finalize the 2015 entering class (there is still some wait list movement now) and get them all on campus before they worry about sending 2016 secondaries
The consensus is that most applicants get secondaries. U. Washington and EVMS are notorious prescreeners: the former only allows WWAMI applicants to apply.