In the United States, two organizations issue nationally recognized credentials for medical interpreters: the Certification Commission for Healthcare Interpreters (CCHI) and the National Board of Certification for Medical Interpreters (NBCMI). Most hospital procurement teams accept either one. They differ in which languages are tested, in some of the exam mechanics, and in accreditation status.
CCHI credentials
CCHI offers a knowledge-based credential called CoreCHI (a written examination covering medical terminology, ethics, and interpretation theory, applicable to interpreters of any language) and the performance-based CHI credential, currently available in Spanish, Arabic, and Mandarin. CCHI also offers CoreCHI-P, a performance-based version of the core credential. CCHI's CoreCHI, CoreCHI-P, and CHI-Spanish credentials are accredited by the National Commission for Certifying Agencies (NCCA), which makes them the only NCCA-accredited interpreter certifications in the United States as of this writing.
The CHI performance examination tests consecutive, simultaneous, and sight translation in the candidate's language pair, on top of the knowledge-based written component.
NBCMI credentials
NBCMI issues a written credential called HubCMI (formerly known as Hub-CMI) that is valid for all languages, and a performance-based CMI (Certified Medical Interpreter) credential in six languages: Spanish, Cantonese, Mandarin, Korean, Russian, and Vietnamese. The CMI examination format includes a written component and an oral component. NBCMI held NCCA accreditation in earlier years for its Spanish credential but stepped away from NCCA accreditation in 2018 to reallocate resources to other languages.
Prerequisites
Both bodies require candidates to have completed a 40-hour medical interpreter training program from a qualifying provider before sitting for the examinations. Both require demonstration of professional-level proficiency in English and the target language. Both require continuing education to maintain certification.
Which one to look for
Practically, either credential is sufficient evidence of professional medical interpretation training. Some healthcare networks specify one over the other; most accept either. When you book a medical interpreter through AMS, ask which certification the assigned linguist holds and we will confirm in writing. For high-stakes interactions (surgical consents, mental health assessments, IMEs), the right interpreter is one with the relevant certification plus subject-matter experience in your specialty.
What neither credential does
Neither CCHI nor NBCMI certifies subject-matter expertise. A nationally certified medical interpreter is qualified to interpret in clinical settings generally, but a complex psychiatric evaluation, a pediatric oncology consult, or an orthopedic IME each benefit from an interpreter who has seen the specialty before. When booking, mention the specialty so the right linguist can be matched.