to extend visit visa you may have gone through medical test.if it is not more than 6 months,your old record is available.what you need now,get your passport,new visa approval and keep100 qrs handy and go to medical comission they may consider your old record and after some paper work they will give you another certificate or they may test again.result after 4 days,then you have to go to finger print.if your sponsor is company your mandoob will take you to right place.
good luck