Dear Mr Lawal.
Traveling for medical check up in abroad need some genuity. Firstly, you must produced some document from your hospital here in Nigeria assigned with your Doctor indicationg your illness condition and beside, your hospital in china should have related arrangment with your Nigeria hospital which should be well prepared by both of them, then Your hospital in china will help you to acquired the invitation letter from the bureau in china, which will allowed the consular to issued you a visa for medical check up in China.
Please Mr lawal note: Patient card does not guarantee you a visa to travel to china.