Are anti rh antibodies are present in normal serum?

Yes, anti-Rh antibodies can be present in normal serum, but typically in very small amounts. These antibodies are primarily found in individuals who have been sensitized to Rh antigens, often through previous blood transfusions or pregnancies involving Rh-positive blood. In the general population, most Rh-negative individuals do not have detectable anti-Rh antibodies unless they have been exposed to Rh-positive blood.