Hi Kaus
We are also heading to Aussie on 457 visas from South Africa, my wife and I only needed chest xrays and the kids a medical examination. Not blood tests etc where required, I think they will require those tests once we apply for permanent residence. Our visas have been lodged in Aussie by the company who is employing me and should take 6 to 8 weeks.
Regards
Andy Laing