A cma (certified medical assistant) can generally perform most garden variety doctor office type procedures/tasks such as taking brief history, charting for doc, taking/recording VS, administering shots, a brief list of things that most lpns in doc's offices do.
A cna (certified nursing assistant) is not educated/certified to perform injections or help with procedures done in a doctor's office unless the doctor him or herself have taken time to train that cna to do those specific things. As with all variances state to state, it is best to check with the state board of nursing which also regulates cnas to determine what you are legally required to do in either role.
You would actually be overqualified as a cma versus a cna if you want to work in a ltc setting. But I'm sure they'd consider you as a potential employee if you don't mind working at the lower per hour rate that cnas usually pull in as compared to cmas.Hope this helps clarify.