Form N-648, Medical Certification for Disability Exceptions, lets an applicant for naturalization request an exception to the English-language and/or civics (history and government) testing requirements when a physical or developmental disability or mental impairment prevents them from meeting those requirements. Unlike the immigration medical examination on Form I-693, Form N-648 does not require a USCIS-designated civil surgeon: it may be completed by a licensed medical doctor (MD), doctor of osteopathy (DO), or licensed clinical psychologist authorized to practice in the United States. The certifying provider describes the applicant’s condition and explains how it prevents compliance with the testing requirements. The form is submitted in support of Form N-400 and is typically reviewed at the naturalization interview. Because a broader range of clinicians can complete N-648, it represents a distinct service category from the civil-surgeon-only I-693 exam.