This is one perfect example as to why you should have an Attorney.  Under the Social Security Rules, if Social Security wants to send you off for a Consultive Evaluation with a doctor, the rules say that your own doctor is the preferred choice.  Social Security must  contact your doctors to seek medical information.  If SSA does not receive the requested information from your doctors, the rules require SSA to re-contact your doctor and ask for the information unless to do so would be futile.  After SSA has exhausted the above efforts, only then may SSA send you to a Social Security doctor.  If SSA fails to comply with the above requirements, SSA is not allowed to ask you to visit an SSA doctor.   SSA regularly violates these rules.  However, if you fail to attend, you run the risk that SSA will claim you failed to cooperate in the development of your claim and may deny benefits on that basis.  As to whether you attend or not is a strategic decision that you, as a Claimant, do not want to make.  It is a decision that should be made only by a qualified Attorney.   If you don=t have an Attorney and you receive such a notice of a medical exam, you should contact an attorney immediately to decide whether it would be strategically advantageous to not attend.  In more recent years, Social Security has taken a stronger position and has looked very unfavorably upon those that do not attend their exams by an SSA doctor.