Medical providers are required to have proof that those who work with them have HIPAA training. The Department of Health and Human Services has published a summary of HIPAA.
Interpreters are Business Associates under HIPAA. I believe that voluntary compliance will help interpreters demonstrate that they are proactive about complying with HIPAA requirements and will also help interpreters understand the legal boundaries of the information they can share.
The HIPAA Group, Inc. has been in business for more than 12 years and serves hundreds of universities and thousands of healthcare entities and business associates. This is a link to their Compliance Guide for Business Associates and Covered Entities.
This is a link to the course description for the online course for Business Associates, which applies to medical interpreters. This is the link to register. The cost is $25 and it takes about an hour to complete it. They issue a certificate of successful completion immediately, online.