Transfer of earned credits from non-accredited schools to accredited schools is virtually impossible, though exceptions for schools outside of the US do exist. Transfer of credits can also be difficult from nationally accredited educators like ITT Tech to regionally accredited schools like the University of Pittsburgh.

It's generally much easier to transfer credits from a regionally accredited program to one that is nationally accredited, or between two nationally accredited institutions.

There are many reasons for this difficulty, including curriculum, admission, and instructional differences. Admission policies are often more stringent at regionally accredited schools, curriculum is more diverse, and performance metrics like GPA are more important. Nationally accredited schools offer focused, practical programs that may not translate as easily into programs at regionally accredited institutions.

Once again, this does not mean necessarily that the education recieved at a nationally accredited institution is inferior. It simply means that regionally accredited schools have more stringent academic policies.

There is never any guarantee that credits will transfer. Transfer of credits is extremely complicated; even transferring credits between regionally accredited institutions  can be difficult.

Remember that accreditation status, whether regional or national, is an unbiased stamp of approval and ensures that the education you receive has itself been judged by a stringent evaluation process, and will be of a certain level of quality. Regional accreditation denotes an education that is generally more encompassing than one recieved at a nationally accredited institution (which usually focuses on a specific trade).

If you have credits you want to transfer, talk to your admissions counselor before you enroll. If the credits will not transfer, consider continuing your search. Who wants to start their education again from scratch if the credits you've already acquired are unable to transfer?

Even if you don't currently have any earned credits to transfer, you may eventually. If you decide to change schools for any reason, you'll want to transfer the credits you've earned. There are many exceptional online institutions which are regionally accredited. Credits earned at these institutions are generally more easily transfered.