Review neonatal jaundice context using Bhutani nomogram zones, simplified AAP 2022 reference thresholds, bilirubin rise, and direct-bilirubin fraction.
Neonatal hyperbilirubinemia is common in the first days of life, which is why bilirubin values are usually interpreted against postnatal age in hours rather than with a single all-purpose cutoff. Most newborn jaundice is physiologic, but higher values, fast rises, or unusual direct-bilirubin fractions can change how closely a baby needs to be watched.
This calculator uses the Bhutani hour-specific bilirubin nomogram to place a bilirubin result into a reference zone based on total serum bilirubin (TSB) and postnatal age. It also shows simplified gestational-age and risk-factor-adjusted phototherapy and exchange reference thresholds, estimates rate of rise, and flags when the direct-bilirubin fraction looks high enough to deserve separate clinical attention.
The goal is to keep those reference points together in one worksheet. It is meant for screening and interpretation support, not as a stand-alone treatment protocol.
Newborn jaundice changes quickly, so the useful question is not only how high the bilirubin is, but whether it is rising faster than expected for the baby's age and risk profile. This calculator keeps the hour-specific zone, treatment threshold, and conjugated fraction together so the interpretation stays tied to the actual postnatal timing.
Bhutani zone: hour-specific TSB percentile classification. Simplified phototherapy reference threshold ≈ 18 mg/dL (≥38 wks, low risk), adjusted downward for prematurity and risk factors. Simplified exchange reference threshold ≈ 25 mg/dL with similar adjustments. Rate of rise = TSB / (age in hours / 24); rapid rise >0.2 mg/dL/hr can suggest hemolysis or a need for closer review.
Result: High-Intermediate zone (75th–95th percentile), simplified phototherapy reference threshold 18 mg/dL, below that threshold on this page
A TSB of 14 mg/dL at 48 hours in a healthy term infant falls in the high-intermediate Bhutani zone. On this worksheet it remains below the simplified phototherapy reference threshold, but the hour-specific zone and the overall clinical picture still matter for follow-up decisions.
The same bilirubin value has a different meaning at 18 hours than it does at 72 hours. That is why hour-specific plotting is more clinically useful than a single cutoff, especially in infants discharged early or those with risk factors for hemolysis or poor intake.
Gestational age and neurotoxicity risk factors move the phototherapy and exchange thresholds downward. Those adjustments matter because late preterm infants and babies with hemolysis, sepsis, or low albumin can reach a treatment threshold sooner than a healthy term infant.
The rate of rise is often the clue that a newborn is moving toward a higher-risk zone faster than expected. Serial measurements are more informative than one isolated number, particularly when the first result is near a reference boundary.
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This page keeps several bilirubin reference concepts together in one worksheet: Bhutani hour-specific risk-zone placement, simplified AAP 2022-style phototherapy and exchange-threshold context, bilirubin rate of rise, and direct-bilirubin fraction screening. The AAP treatment thresholds shown here are intentionally simplified rather than reproduced as a clinical tool, so the result should be used for review and follow-up planning, not as a stand-alone treatment order set.
No. This page shows simplified AAP-style reference thresholds for educational context. Actual phototherapy decisions still depend on the infant’s age, gestational age, neurotoxicity risk factors, exam findings, and the full clinical setting.
The Bhutani nomogram is a chart that plots total serum bilirubin against postnatal age in hours, classifying infants into low-risk, low-intermediate, high-intermediate, and high-risk zones to predict the likelihood of subsequent severe hyperbilirubinemia. It is most useful when you want to compare a single bilirubin result against the expected age-specific distribution.
Breastfeeding jaundice (early, days 2–5) occurs due to inadequate milk intake causing dehydration and reduced bilirubin elimination. Breast milk jaundice (late, weeks 1–12) involves substances in breast milk that inhibit hepatic bilirubin conjugation. Both are manageable with feeding support.
There is no single bilirubin level that is concerning at every age. The same TSB can mean very different things at 24 hours versus 96 hours, which is why hour-specific context and gestational age matter so much.
A faster bilirubin rise can suggest hemolysis or a newborn who is moving toward a higher-risk zone more quickly than expected. This page uses >0.2 mg/dL/hr as a screening flag, not as a diagnosis by itself.
Direct (conjugated) bilirubin deserves separate clinical review when it is clearly elevated in absolute terms or makes up an unusually large share of the total bilirubin. This page uses common screening cutoffs to flag that possibility, not to diagnose the cause.