Medical certificate is compulsory before applying for Chinese visa not more than 2-3 month?

I am studying in china since 2015; i want to invite my wife for visit 2-3 months only
As far as i know these documents are required;

1. Invitation letter from individual staying in China

2. Original Passport of applicant (2 photo graphs)

3. Marriage certificate showing the relation attested by Ministry of foreign affairs Pakistan

4. Police certificate attested by Ministry of foreign affairs Pakistan

5. If there are any other documents particularly medical /physical examination report please let us know

Please guide