Very interesting...not very familiar with this field myself, but do know that it is very important work that is focused on ensuring that non-english speakers are able to feel comfortable in healthcare settings.
I'd recommend you visit the following sites to learn a bit more about the industry...
International Medical Interpreters Association
On that site, you can learn more about how to get trained / certified in the profession.
National Board of Certification for Medical Interpreters
Appears that a college degree isn't required, but I imagine that it would help you significantly in the long run in the industry...perhaps consider a degree in Healthcare and/or Communication (+ Foreign Language if you aren't already fluent). Know that there are specific certificate programs in Medical Interpretation as well.
Good luck to you!
Hope this helps.