Delta bilirubin in serum of pediatric patients: correlations with age and disease

Area of Science:

• Clinical Chemistry
• Pediatric Gastroenterology
• Neonatology

Background:

• Bilirubin metabolism is complex, with several fractions identifiable by liquid chromatography.
• The delta bilirubin fraction (B delta), covalently bound to albumin, is less understood.
• Accurate assessment of bilirubin fractions is crucial for diagnosing and managing liver and hematologic disorders in children.

Purpose of the Study:

• To investigate the incidence and clinical significance of the delta bilirubin fraction (B delta) in infants and children.
• To correlate B delta levels with patient age and disease course.
• To evaluate the potential interference of B delta with routine bilirubin assays.

Main Methods:

• Serum samples from 539 infants and children were analyzed.
• Liquid chromatography was used to separate and quantify bilirubin fractions, including B delta.
• Results were compared with the routine colorimetric Jendrassik-Grof method.

Main Results:

• B delta proportion generally was <2% in infants <28 days old.
• Median B delta was 35% in hyperbilirubinemic older infants and children.
• High B delta (>50%) in newborns was linked to cholestasis and biliary disorders.
• Low B delta (<10%) in older children was associated with hemolytic anemias, sepsis, and shock.
• Low B delta with increased conjugated bilirubin indicated a poor prognosis.

Conclusions:

• The delta bilirubin fraction (B delta) levels correlate with age and disease status in pediatric populations.
• Elevated B delta is indicative of cholestatic conditions in newborns.
• Low B delta, particularly with elevated conjugated bilirubin, may signify a poor prognosis in older children.
• The presence and clearance rate of B delta can impact the interpretation of conjugated bilirubin measurements by standard methods.