What is the significance of elevated total serum bilirubin level in the evaluation of unconjugated hyperbilirubinemia?

Updated: May 21, 2019
  • Author: Hisham Nazer, MBBCh, FRCP, DTM&H; Chief Editor: BS Anand, MD  more...
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All patients with impaired bilirubin conjugation have an elevated total serum bilirubin level that is due primarily to the unconjugated form; however, the level of elevation varies according to the underlying disease process.

Transient elevation of plasma bilirubin may be seen in healthy neonates. The plasma bilirubin usually returns to normal within 10 days. For infants in whom the plasma bilirubin level remains elevated, search for the inherited disorders of bilirubin metabolism.

In neonates, transcutaneous devices that use multiwavelength spectral reflectance can be used to estimate total serum bilirubin levels and avoid blood sampling. At higher total serum bilirubin levels, the transcutaneous measurements may underestimate the total serum bilirubin concentration; therefore, serum measurements should be obtained. Also, the transcutaneous measurements are not reliable in infants undergoing phototherapy.

In a study, Cakmak et al suggested that by measuring haptoglobin levels from the cord blood, neonatologists and pediatricians could stratify neonates into high- versus low-risk groups for developing jaundice, leading to earlier intervention. Because haptoglobin levels decrease during hemolysis, which in turn plays a significant role in raising bilirubin levels in neonates, the investigators examined the relationship between decreasing haptoglobin levels and the risk of jaundice in 84 term babies. [64]

The average gestational age of the mothers was 39.5 ±1.5 weeks. The authors noted a negative correlation between haptoglobin levels drawn from the umbilical cord blood and bilirubin values on the fifth postpartum day.

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