Well there are a few different ones available. One that I found was after you finish the Medical Assistant certification you can take the national certification test to become Registered Medical Assistants. see here http://www.sbbcollege.edu/medical-assisting.asp
You can try inquiring at Certified Medical Assistant (CMA) or at Registered Medical Assistant (RMA). This will look good on the medical assistant job description. Visit http://whatdoesamedicalassistantdo.com/ for more info.