It's kind of important to note that "post-bac" studies may or may not lead to a degree. It depends on the situation.
For those who have a bachelor's degree but never completed the premedical sciences, "post-bac" studies generally consist of simply taking the pre-medical sciences in order to be eligible to apply for medical school. At some universities this may lead to a certificate, but rarely if ever an actual degree. There are organized post-bac pre-med programs at some colleges and universities in the US, while other students simply elect to take the pre-med science classes on their own. Either way is viable.
In addition, though, graduate studies (masters or doctoral level) are also technically "post-bac" because they occur after the completion of a bachelor's degree.
It is important to make sure that you know precisely which scenario applies to you, and what kind of "post-bac" studies you need for your situation.
"When I haven't any blue... I use red."
- Pablo Picasso