Getting certified as a medical assistant is one of the best things you can do to appeal to potential employers. Certification means you have proven yourself against a nationwide standard; in short it provides a measuring stick for you and other potential hires to be compared with. In the absence of experience, a certification can make all the difference.
There are a number of local, state, and national agencies in charge of certified medical assistants. The certification process varies across these, however almost all of them will require you to pass a written exam as well as some sort of formal demonstration of technique and knowledge in a health care provider setting. It is also possible to become certified in a specialty of medical assistants, for example ophthalmology, podiatry, pediatrics, etc.