http://uscis.gov/graphics/formsfee/forms/i-693.htm
The results of the medical examination are generally valid for only 12 months. Applicants should schedule the medical examination as close as possible to the time you file for Adjustment of Status.
The results of the medical examination are generally valid for only 12 months. Applicants should schedule the medical examination as close as possible to the time you file for Adjustment of Status.