There are many differences between a CNA and a Medical Assistant. There are differences in the training they receive and the work they perform. A CNA can be trained and certified within 3 weeks, with a minimum of 100 hours required. Most Medical Assistant programs are up to one year long. To qualify for the AMT exam, there is a minimum of 880 invested hours. The coursework covered in CNA is focused toward geratric care in a long-term care facility. Medical Assistant training is focused toward acute care and goes beyond direct patient care to cover administrative duties, as well.