Students must take a standardized test as part of their application to health professions school. Each test differs somewhat in subject matter. They all test reading comprehension, critical thinking skills, problem-solving ability, and subject area knowledge.
Students should take the exams after they have taken classes in the subject areas covered. For example, medical applicants will have taken General Chemistry, and some or all of Biology, Organic Chemistry and Physics before they take the Medical College Admission Test (MCAT). Be aware that in addition to testing in the sciences, the MCAT tests Verbal Reasoning and Writing skills -- if you feel like you need work in these areas, you are encouraged to take classes that will help you to build these skills.
More information about standardized tests is covered in our Questions of the Week, and in great detail in the Applicant Handbook.