I got email from NVC that my parents' cases have been sent to Guangzhou. We need to wait for notice to interview.
Do you know what documents they need ?
-The Consulate will send your parents a list of required documents, normally it includes your parents birth certificates, non-criminal record certificates (equal to Police Clearance Certificate in US), their marriage certificate, their physical exam report conducted in a US Consulate authorized hospital in China, etc. If you have provide some of these original documents to NVC, your parents do not need to provide them.
Is the designated medical test location close to the embassy?
-I don't know.
May they get the results on the same day?
-It is possible, case by case.
Just worry about their travel to Guangzhou.