Lab

Neonatal Bilirubin

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Neonatal Bilirubin, Bilirubin in Newborns

  • See Also
  1. Bilirubin
  2. Neonatal Jaundice
  3. Neonatal Jaundice Causes
  4. Phototherapy
  5. Exchange Transfusion in Newborns
  6. Liver Function Test
  7. Liver Function Test Abnormality
  • Precautions
  1. Transcutaneous Bilirubin (TcB) measurement correlates well with total Serum Bilirubin (TSB) at lower levels (regardless of ethnicity)
  2. However, obtain TSB, when TcB >15 mg/dl (256.6 umol/L) or within 3 mg/dl (51.3 umol/L) of a Phototherapy threshold
  3. References
    1. Holland (2009) Am J Clin Pathol 132(4): 555-61 [PubMed]
    2. Bhutani (2000) Pediatrics 106(2): E17 [PubMed]
    3. Campbell (2011) Paediatr Child Health 16(3): 141-5 [PubMed]
  • Interpretation
  • Normal Total Bilirubin in Newborns
  1. General
    1. Normal Increase <5 mg/dl/day (<0.5 mg/dl/hour)
    2. Conjugated Bilirubin (Direct) fraction <2 mg/dl
  2. Term Infant
    1. Peaks: 12.9 at 3 to 4 days of life
    2. Resolves at 4 to 7 days of life
  3. Preterm Infant
    1. Peaks: 15.0 at 5 to 7 days
    2. Resolves at 10 to 14 days of life
  4. Exagerated Physiologic Jaundice
    1. Peaks 17.0 at age 6 to 8 days of life
  5. Early-Onset Breast Milk Jaundice
    1. Same course as exaggerated physiologic Jaundice
    2. Total Bilirubin peaks < 17 mg/dl by day 4 of life
  6. Late-Onset Breast Milk Jaundice
    1. Bilirubin peaks between day of life 6 to 14 of life
    2. Total Bilirubin often 12 to 20 mg/dl
    3. Hyperbilirubinemia may persist 2-3 months
  • Indications
  • AAP 2022 - Phototherapy in LOW risk TERM infants (>36 weeks and >2 kg, or >35 weeks and >2.5 kg)
  1. Background
    1. Use BiliTool or PediTools calculators for exact indication thresholds (thresholds here are rough estimates summarizing guidelines)
    2. Thresholds updated in AAP 2022 are considerably higher than prior thresholds for initiating Phototherapy
    3. The upper range reflects the indication for exchange transfusion (Escalate care to NICU when within 2 mg/dl of upper threshold)
  2. Gestational age 40 weeks - Thresholds
    1. Age 24 hours: >=13.0 mg/dl to 21.5 mg/dl
    2. Age 48 hours: >=17.0 mg/dl to 24.0 mg/dl
    3. Age 72 hours: >=19.5 mg/dl to 26.0 mg/dl
    4. Age 96 hours: >=21.5 mg/dl to 27.0 mg/dl
  3. Gestational age 38 weeks - Thresholds
    1. Age 24 hours: >=12.0 mg/dl to 21.5 mg/dl
    2. Age 48 hours: >=16.0 mg/dl to 24.0 mg/dl
    3. Age 72 hours: >=18.5 mg/dl to 26.0 mg/dl
    4. Age 96 hours: >=20.5 mg/dl to 27.0 mg/dl
  4. Gestational age 36 weeks - Thresholds
    1. Age 24 hours: >=11.0 mg/dl to 21.0 mg/dl
    2. Age 48 hours: >=14.5 mg/dl to 22.0 mg/dl
    3. Age 72 hours: >=17.5 mg/dl to 24.0 mg/dl
    4. Age 96 hours: >=19.5 mg/dl to 25.5 mg/dl
  5. References
    1. Kemper (2022) Pediatrics 150(3): e2022058859 [PubMed]
  • Indications
  • AAP 2022 - Phototherapy in HIGH risk TERM infants (>36 weeks and >2 kg, or >35 weeks and >2.5 kg)
  1. Background
    1. Use BiliTool or PediTools calculators for exact indication thresholds (thresholds here are rough estimates summarizing guidelines)
    2. Thresholds updated in AAP 2022 are considerably higher than prior thresholds for initiating Phototherapy
    3. High risk factors for neurotoxicity include Hemolysis (e.g. g6PD, Hemolytic Disease of the Newborn), Sepsis, instability, albumin <3 g/dl
    4. The upper range reflects the indication for exchange transfusion (Escalate care to NICU when within 2 mg/dl of upper threshold)
  2. Gestational age 38 to 40 weeks - Thresholds
    1. Age 24 hours: >=10.5 mg/dl to 17.5 mg/dl
    2. Age 48 hours: >=14.0 mg/dl to 20.0 mg/dl
    3. Age 72 hours: >=16.5 mg/dl to 22.0 mg/dl
    4. Age 96 hours: >=18.0 mg/dl to 23.5 mg/dl
  3. Gestational age 36 weeks - Thresholds
    1. Age 24 hours: >=9.5 mg/dl to 16.5 mg/dl
    2. Age 48 hours: >=12.5 mg/dl to 19.0 mg/dl
    3. Age 72 hours: >=15.5 mg/dl to 21.0 mg/dl
    4. Age 96 hours: >=17.0 mg/dl to 22.0 mg/dl
  4. References
    1. Kemper (2022) Pediatrics 150(3): e2022058859 [PubMed]
  • Resources
  1. Bilirubin Tool
    1. http://www.bilitool.com
  2. PediTools
    1. https://peditools.org/bili2022/
  • References
  1. Ip (2004) Pediatrics 114(1): e130-53 [PubMed]
  2. Bhutani (1999) Pediatrics 103:6-14 [PubMed]
  3. Varvarigou (2009) Pediatrics 124(4): 1052-9 [PubMed]