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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 credential for interpreters of any language, earned by passing the CoreCHI exam plus the English-to-English ETOE interpreting exam. CCHI is phasing out the standalone CoreCHI: from January 1, 2027, it will award only CHI and CoreCHI-P. CCHI's CoreCHI, CoreCHI-P, and CHI-Spanish credentials are accredited by the National Commission for Certifying Agencies (NCCA). CCHI says these are the only accredited interpreter certifications in the United States.
The CHI performance examination, taken after passing CoreCHI, tests consecutive and simultaneous interpreting and sight translation in the candidate's language pair.
NBCMI credentials
NBCMI issues a written credential called 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's Spanish CMI credential was formerly accredited by the NCCA, but that accreditation ended in 2018, when NBCMI says it brought all its CMI programs under the same set of standards.
Prerequisites
Both bodies require candidates to have completed at least 40 hours of medical interpreter training before sitting for the examinations (NBCMI also accepts 3 college credit hours). Both require proof of 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.