Bilirubin and Bilirubin Fractions

Bilirubin and Bilirubin Fractions is a topic covered in the Davis's Lab & Diagnostic Tests.

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Nursing Central


Conjugated/direct bilirubin, unconjugated/indirect bilirubin, delta bilirubin, TBil.

A multipurpose laboratory test that acts as an indicator for various diseases of the liver, for disease that affects the liver, or for conditions associated with red blood cell (RBC) hemolysis.

Patient Preparation

Normal Findings
(Method: Spectrophotometry) Total bilirubin levels in infants should decrease to adult levels by day 10 as the development of the hepatic circulatory system matures. Values in breastfed infants may take longer to reach normal adult levels. Values in premature infants may initially be higher than in full-term infants and also take longer to decrease to normal levels.

AgeConventional UnitsSI Units (Conventional Units × 17.1)
Total bilirubin
 Newborn–1 dLess than 5.8 mg/dLLess than 99 micromol/L
 1–2 dLess than 8.2 mg/dLLess than 140 micromol/L
 3–5 dLess than 11.7 mg/dLLess than 200 micromol/L
 6–7 dLess than 8.4 mg/dLLess than 144 micromol/L
 8–9 dLess than 6.5 mg/dLLess than 111 micromol/L
 10–11 dLess than 4.6 mg/dLLess than 79 micromol/L
 12–13 dLess than 2.7 mg/dLLess than 46 micromol/L
 14–30 dLess than 0.8 mg/dLLess than 14 micromol/L
 1 mo–older adultLess than 1.2 mg/dLLess than 21 micromol/L
Unconjugated bilirubinLess than 1.1 mg/dLLess than 19 micromol/L
Conjugated bilirubin
 NeonateLess than 0.6 mg/dLLess than 10 micromol/L
 29 d–older adultLess than 0.3 mg/dLLess than 5 micromol/L
Delta bilirubinLess than 0.2 mg/dLLess than 3 micromol/L

Critical Findings and Potential Interventions

Adults and Children

  • Greater than 15 mg/dL (SI: Greater than 257 micromol/L)


  • Greater than 13 mg/dL (SI: Greater than 222 micromol/L)


Consideration may be given to verification of critical findings before action is taken. Policies vary among facilities and may include requesting recollection and retesting by the laboratory.

Sustained hyperbilirubinemia can result in brain damage. Kernicterus refers to the deposition of bilirubin in the basal ganglia and brainstem nuclei. There is no exact level of bilirubin that puts infants at risk for developing kernicterus. Symptoms of kernicterus in infants include lethargy, poor feeding, upward deviation of the eyes, and seizures. Intervention for infants may include early frequent feedings to stimulate gastrointestinal (GI) motility, phototherapy, and exchange transfusion.
