Bilirubin binding in jaundiced newborns: from bench to bedside?

BACKGROUND

Bilirubin-induced neurologic dysfunction (BIND) is a spectrum of preventable neurological sequelae in jaundiced newborns. Current total plasma bilirubin (B) concentration thresholds for phototherapy and/or exchange transfusion poorly predict BIND.

METHODS

The unbound (free) bilirubin (B) measured at these B thresholds provides additional information about the risk for BIND. B can be readily adapted to clinical use by determining B population parameters at current B thresholds. These parameters can be established using a plasma bilirubin binding panel (BBP) consisting of B, B, and two empiric constants, the maximum B (B) and the corresponding equilibrium association bilirubin constant (K).

RESULTS

B and K provide the variables needed to accurately estimate B at B < B to obtain B at threshold B in patient samples. Once B population parameters are known, the BBP in a newborn can be used to identify poor bilirubin binding (higher B at the threshold B compared with the population) and increased risk of BIND.

CONCLUSION

The BBP can also be used in jaundice screening to better identify the actual B at which intervention would be prudent. The BBP is used with current B thresholds to better identify the risk of BIND and whether and when to intervene.