My interview hasn't been scheduled yet, but I want to get started on my medical exam. Where should I go to get an exam?
You will receive instructions concerning interview preparation in the appointment letter that you will receive from the NVC. You should not have your exam until your interview has been scheduled.

IMPORTANT NOTE:Medical examination results are valid for one year in normal circumstances. But if you have certain medical conditions your examination results could expire in as little as 3 months. In any case you should not have your medical examination until the NVC notifies you of your interview appointment date. You may be denied entry to the United States if your medical examination results expire before your arrival.