Hemolytic disease of fetus or newborn due to ABO isoimmunization

This code describes a condition in a fetus or newborn where red blood cells are destroyed prematurely due to an incompatibility between the mother's and baby's ABO blood types. This isoimmunization leads to hemolysis, which can manifest as jaundice, anemia, and other complications in the neonate.

Assign this code when documentation clearly indicates hemolytic disease in a fetus or newborn specifically attributed to ABO incompatibility. This typically occurs when the mother is type O and the baby is type A or B, and maternal antibodies cross the placenta to attack fetal red blood cells. Supporting documentation would include blood type results for mother and baby, positive direct Coombs test in the infant, and clinical signs of hemolysis.

• Differentiate carefully from Rh isoimmunization (e.g., 773.0), as the underlying immunological mechanism and clinical management differ.
• Ensure the documentation explicitly states "ABO isoimmunization" or provides sufficient detail to confirm this specific type of hemolytic disease.
• Code any associated clinical manifestations, such as severe neonatal jaundice (e.g., 774.2), as secondary diagnoses.