I live in Utah, where the state has had it's own certification program for Medical Interpreters since 2009. Unfortunately, since it was created before the National Board was up and running, all it took to become a "certified medical interpreters" in Utah was taking Bridging the Gap, and pay a $50 fee. No language assessment, no test, no continued education--that was it.  

After many years of complaining to the senator that sponsored the original bill, she agreed to hold a meeting of stakeholders and this year the law was revised and changed to require national certification instead, so I am very happy that the state realized the importance of not only testing the language proficiency of the interpreters, but that it has recognized the validity of the National Board and it's standards.  For languages that are not nationally certifiable yet (no oral exam), they created a tier 2 certification that requires interpreters to pass the written exam from the National Board or the certifying commission, so that they can at least demonstrate adequate knowledge of the field, and meet the pre-requisites in education.