ALB and kernicterus: What was not known in the 1930s was that unconjugated bilirubin binds tightly to plasma albumin and a key factor (but not the only one) in the occurrence of kernicterus is when the binding capacity of albumin for unconjugated bilirubin is exceeded; this form of bilirubin which is highly lipid soluble (in contrast to conjugated bilirubin) enters the brain without restraint.