When a neonate is transfused for the first time with group O Red Blood Cells, appropriate compatibility testing is:

When a neonate is transfused for the first time with group O red blood cells, if the initial plasma screening is negative, crossmatching is not required due to the low likelihood of hemolytic reactions. In this context, a negative initial plasma screening ensures that there are no significant antibodies directed against the antigens found on the donor red blood cells.

This is significant because neonates typically have a limited immune response and may not have developed antibodies to antigens that could cause transfusion reactions, especially if they are receiving group O red blood cells, which are considered universal donors for plasma. Thus, when the plasma screening shows no significant antibodies, it establishes a foundation for safely proceeding with the transfusion without the additional step of crossmatching.

In terms of the other options that are not selected, they involve steps that are unnecessary when the initial screening indicates no antibodies or when using group O cells. This underscores the importance of the initial screening process to determine the necessity of additional compatibility testing before the transfusion.