Many years ago, I was a medical secretary in a busy GP practice. It was a fantastic grounding for becoming a medical translator because of the variety of documents involved.
To be able to provide a high standard of translation, I am studying towards a BSc in Health Science with the Open University. I have also taken various other CPD courses and subscribe to the BMJ.
In addition to translation, if the document you are writing is for publication I can check the document against any style guide you have. I can also provide a summary of journal articles etc. before you commit to a full translation.