What does HB stand for?

Hyperbilirubinemia

An elevated level of the pigment bilirubin in the blood. A sufficient elevation of bilirubin produces jaundice. Some degree of hyperbilirubinemia is very common right after birth, especially in premature babies. Treatment of hyperbilirubinemia in the newborn involves exposure of the skin to special lights and removal of serum from the blood and replacing with solutions free of bilirubin (exchange transfusion).