However, bilirubin can cross the blood-brain barrier and cause kernicterus in certain situations: When serum bilirubin concentration is markedly elevated When serum albumin concentration is markedly low (eg, in preterm infants) When bilirubin is displaced from albumin by competitive binders Competitive binders include drugs (eg, sulfisoxazole, ceftriaxone, aspirin) and free fatty acids and hydrogen ions (eg, in fasting, septic, or acidotic infants).