It is fairly common for Social Security Disability claimants to receive a letter stating that they have to be examined by a doctor appointed by the Social Security Administration. In Social Security talk, this medical examinations are called "consultative examinations" or "CE's".
These examinations are usually ordered when the Social Security examiner in charge of the case feels that there isn't enough up to date medical information on the file. As a general rule, claimants should not get too stressed out about a CE. In my experience as a Social Security lawyer, CE's rarely make a difference in winning or loosing a case. However, it is extremely important for the claimant to attend the examination and to be cooperative during the process.
It must be pointed out that the doctor who conducts the CE is not an employee of the Social Security Administration. These doctors are independent physicians who have a contract with the SSA to examine claimants. Their examinations are usually very short (sometimes a short as 5 to10 minutes).
Once the doctor completes a CE, he or she writes a report regarding the claimant's physical or mental conditions. These reports are usually very vague and add very little to a case. Since most doctors spend very little time conducting a CE, I usually argue successfully that their findings or opinions should be given very little weight.
The most important thing to remember, when going to a consultative examination, is that the doctor who conducts it is probably not on your side. For this reason, you must be very careful not tell him or her any information that could prejudice your case. It is also very important to remember to tell the doctor all your pain and/or mobility issues that you may have. Finally, be aware that these doctors will often observe what you do since the time that you enter their office parking lot and will ask you specific questions as to how you arrived at the appointment.