Question normal

My question is when exactly the coronavirus patient could be contagious?
As an orthopedic surgeon in Germany, I contacted a patient which he is now corona positive, the health office told if he doesn't have any symptoms he could not be contagious? At least 2 days before the first system!!
is that mean asymptomatic patient with corona virus.. Not dangerous?
by the way, they asked me to work even I was exposed and they don't won't take even sample?? Is that ok !
best regards