Which tests are typically included in a standard prenatal workup?

• A. ABO, Rh, antibody screen
• B. Direct antiglobulin test, crossmatch, infectious disease screen
• C. Hgb, bilirubin, LDH
• D. Platelet count, coagulation studies, reticulocyte count

Answer: (A)

The main idea here is preventing alloimmune challenges to the fetus by checking the mother's red cell antigens and antibodies. In a standard prenatal workup, knowing the mother’s ABO and Rh type is essential to identify potential Rh incompatibility and to guide any necessary Rh immune globulin prophylaxis. The antibody screen is then used to detect any unexpected maternal antibodies that could cross the placenta and cause fetal red cell destruction or complicate future transfusions for the newborn. If the screen is negative, the risk of hemolytic disease from maternal antibodies is low; if it’s positive, the specific antibody is identified and management plans for the pregnancy and neonatal period are developed.

Direct antiglobulin testing is typically used after birth to evaluate hemolysis in the newborn, not as a routine prenatal screening. Crossmatching is a transfusion-specific test used when blood is actually needed for the mother or baby, not part of the standard initial prenatal workup. The other listed laboratory tests (like general blood counts or markers of hemolysis) are useful in certain contexts but do not address the antibody/compatibility assessment central to routine prenatal red cell screening.