All national testing services are required by law to provide reasonable accommodations to test takers with disabilities, and most have detailed information on their websites about how to document a disability and request accommodations. However, students must be self-advocates and get all documentation prepared well in advance. For most tests, the testing services request that all documentation be mailed at least six weeks prior to the registration deadline to be reviewed for approval of accommodations.
The Graduate Record Examination (GRE), Graduate Management Admission Test (GMAT), Test of English as a Foreign Language (TOEFL), and Professional Assessments for Beginning Teachers (PRAXIS) tests are all part of the Educational Testing Service (ETS) testing series. Most graduate schools require students to take the GRE or GMAT (business students) exams for entrance. The TOEFL is required of students who speak English as a second language. The PRAXIS series is required for teacher certification in some states.
To find out more about requesting accommodations for any of these tests, consult the ETS Disabilities & Testing  website, which provides general information about documentation of a disability for ETS and links to information specific to various ETS tests.
Taking the Medical College Admission Test (MCAT) is an entrance requirement for most U.S. medical schools. To request accommodations on the MCAT, a student with a disability should consult the official MCAT  website. The information on disability accommodations can be found at MCAT Disabilities Accommodations.
Taking the Law School Admission Test (LSAT) is required for entrance to law schools in the U.S. Students requesting LSAT accommodations should already be registered to take the test. For information on obtaining accommodations for the LSAT, consult the Law School Admission Council Accommodated Testing website.
-  ETS Disabilities & Testing
-  MCAT