Kernicterus of fetus or newborn due to isoimmunization

This code signifies a severe neurological complication in a fetus or newborn, specifically kernicterus, which results from hyperbilirubinemia caused by isoimmunization. Kernicterus leads to permanent brain damage due to the deposition of unconjugated bilirubin in the brain. The underlying cause is an immune response, typically maternal antibodies, attacking fetal red blood cells.

Use this code when documentation clearly indicates kernicterus in a neonate or fetus, and the etiology is explicitly linked to isoimmunization (e.g., Rh incompatibility, ABO incompatibility). This diagnosis is often made based on clinical signs of bilirubin encephalopathy in the presence of severe hyperbilirubinemia and a positive direct Coombs test.

• Ensure documentation specifies "kernicterus" and not just hyperbilirubinemia, even if severe.
• Confirm the cause is "isoimmunization"; do not use for kernicterus due to other etiologies (e.g., prematurity, sepsis).
• Sequence this code as the primary diagnosis when it is the reason for admission or the main condition being treated.