Yes, we believe it is absolutely necessary to take an MT course to become a medical transcriptionist.  There are many reasons for this but the main reason is that most, if not all, medical transcription companies require 2-5 years of experience before they will even test you for a medical transcription job.  If you take a course through one of the top well known medical transcription schools, many of these same companies will test you right after you graduate, but be forewarned that they will also ask to see a copy of your certificate to prove that you are a graduate.