Newborn Hyperbilirubinemia Assessment — Bhutani Nomogram Calculator
Plot a newborn’s total serum bilirubin (TSB) by age in hours onto the
hour-specific Bhutani nomogram (Bhutani et al., Pediatrics, 1999): the 40th, 75th,
and 95th percentile tracks assign one of four AAP risk zones for significant hyperbilirubinemia.
Includes mg/dL ↔ µmol/L conversion and clinical risk-factor context.
Everything runs in your browser; nothing is uploaded.
Educational screening aid — NOT medical advice. This tool does not
examine the baby and cannot replace a pediatrician’s evaluation. Newborn jaundice needs prompt
evaluation by a clinician.
Seek prompt pediatric care (for example call 119 in Indonesia)
if jaundice appears in the first 24 hours of life, the baby feeds poorly, is unusually sleepy or hard
to wake, has a high-pitched cry, or has dark urine or pale stools.
Risk-zone assessment
Enter the baby’s postnatal age in hours and the total serum bilirubin (TSB).
Domain: 0–144 hours (the nomogram does not extrapolate).
Low-intermediate risk
Measure
Value
Your TSB
40th percentile at this age
75th percentile at this age
95th percentile at this age
Later exceeded the 95th percentile (original study)
Suggested follow-up for this zone
Major risk factors ticked
Needs clinician review. A high or
high-intermediate zone, jaundice under 24 hours, or any ticked risk factor means the baby
should be evaluated by a pediatrician promptly — do not wait for the next routine visit.
Screening aid, not medical advice. Only a clinician who examines the
baby can interpret this result. A low-risk zone still needs routine follow-up at 3–5 days of age.
Clinical risk factors (context, not a score)
Major risk factors for severe hyperbilirubinemia (AAP 2004). Tick any that apply —
they are shown alongside the result for the clinician, not combined into a score.
Minor risk factors:
Nomogram chart
The 40th, 75th, and 95th percentile tracks (mg/dL) from birth to 144 hours. Your point
appears after you run the assessment.
Worked examples (recomputed from the engine)
1 — 36 hours old, TSB 12.5 mg/dL
Percentiles at 36 h: 40th = 7.04, 75th = 8.62, 95th = 10.66 mg/dL.
12.5 ≥ 10.66 → high risk zone (at or above the 95th percentile).
In µmol/L: 12.5 × 17.1 = 213.75. Prompt pediatric evaluation.
2 — 48 hours old, TSB 9.0 mg/dL
Percentiles at 48 h: 40th = 8.72, 75th = 10.66, 95th = 13.18 mg/dL.
8.72 ≤ 9.0 < 10.66 → low-intermediate risk zone.
In µmol/L: 9.0 × 17.1 = 153.90. Follow-up within 48 hours for a term infant.
3 — 96 hours old, TSB 16.0 mg/dL
Percentiles at 96 h: 40th = 14.36, 75th = 15.74, 95th = 17.54 mg/dL.
15.74 ≤ 16.0 < 17.54 → high-intermediate risk zone.
In µmol/L: 16.0 × 17.1 = 273.60. Prompt pediatric evaluation; repeat bilirubin to track the trend.
Methodology
Tracks: piecewise-linear interpolation through the anchor table below
(mg/dL). Zones: TSB ≥ p95 → high ·
p75 ≤ TSB < p95 → high-intermediate ·
p40 ≤ TSB < p75 → low-intermediate ·
TSB < p40 → low. A value exactly on a line belongs to the higher zone.
Units: 1 mg/dL = 17.1 µmol/L.
The 1999 nomogram was published as a figure, not a data table. The tracks above are a
documented reconstruction through published anchors: Newman et al. (JAMA Pediatrics, 2005)
for 0–48 h; Bhosale’s cited Bhutani value of ≈300 µmol/L for the 95th percentile
after 96 h; and Bahr et al. (J. Pediatrics, 2021, co-authored by Bhutani) for the 1999-curve
values at 120 h (95th = 17.6, 75th = 15.8 mg/dL). The 40th-percentile plateau preserves the published
inter-track gap ratio — full derivation in the tool’s SOURCES.md. Spot-checked before release;
see the worked examples above.
Scope boundary: what this tool is (and isn’t)
This tool = the 1999 Bhutani risk-zone screening. Age in hours + total serum bilirubin
→ percentile band → AAP risk zone → follow-up suggestion. Context: unit conversion
and the AAP 2004 clinical risk-factor list.
NOT for preterm infants under 35 weeks or babies in intensive care / with severe
hemolytic disease — the nomogram was not built for them.
NOT a treatment tool. Phototherapy and exchange-transfusion thresholds (AAP 2004/2022)
depend on gestational age and neurotoxicity risk factors — a separate clinical step.
NOT a substitute for pediatric evaluation. A screening zone never replaces examination;
when in doubt, the clinician decides.
Frequently asked questions
What is the Bhutani nomogram?
The Bhutani nomogram is an hour-specific chart of total serum bilirubin (TSB) in newborns, published by Bhutani, Johnson, and Sivieri (Pediatrics, 1999). It was built from predischarge bilirubin measurements of 2,840 healthy term and near-term newborns and draws three percentile lines — the 40th, 75th, and 95th percentiles — for each hour of age from birth to 144 hours. Those lines divide the chart into four risk zones for developing significant hyperbilirubinemia. The American Academy of Pediatrics adopted the nomogram in its 2004 hyperbilirubinemia guideline.
What do the four risk zones mean?
The zones describe where a bilirubin value falls relative to other newborns of the same age in hours: low risk (below the 40th percentile), low-intermediate risk (40th to below the 75th percentile), high-intermediate risk (75th to below the 95th percentile), and high risk (at or above the 95th percentile). In the original study, the share of newborns in each zone who later developed a bilirubin level above the 95th percentile was 0% (low), 2.3% (low-intermediate), 12.9% (high-intermediate), and 39.5% (high). A zone is a screening signal, not a diagnosis — only a clinician can interpret it for an individual baby.
How does this calculator plot my baby’s result?
Enter the baby’s age in hours and the total serum bilirubin (TSB) in mg/dL or µmol/L. The calculator converts the value to mg/dL (1 mg/dL = 17.1 µmol/L), interpolates the 40th, 75th, and 95th percentile lines at that exact age, and assigns the zone: at or above the 95th line is high risk; between the 75th and 95th lines is high-intermediate risk; between the 40th and 75th lines is low-intermediate risk; below the 40th line is low risk. A value exactly on a line is assigned to the higher of the two zones. The chart below the calculator draws the same picture.
How do I convert mg/dL to µmol/L?
Multiply mg/dL by 17.1 to get µmol/L; divide µmol/L by 17.1 to get mg/dL. For example, 12.5 mg/dL × 17.1 = 213.75 µmol/L. This calculator converts automatically when you select µmol/L as the unit.
Which babies does the Bhutani nomogram apply to?
The original nomogram was built from healthy newborns born at 35 or more weeks of gestation. It does not apply to preterm infants below 35 weeks, to babies receiving intensive care, or to babies with severe hemolytic disease — those babies can develop bilirubin toxicity at lower levels and need individualized care from their medical team.
What are the main risk factors for severe jaundice?
The AAP lists major clinical risk factors: jaundice in the first 24 hours of life; blood-group incompatibility or other hemolytic disease (such as G6PD deficiency); gestational age of 35–36 weeks; a previous sibling who needed phototherapy; cephalohematoma or significant bruising; exclusive breastfeeding when nursing is not going well and weight loss is excessive; and East Asian ancestry. You can tick any that apply in the checklist above — they are context for the clinician, not part of a score.
When should I contact a pediatrician about jaundice?
Contact a pediatrician promptly if jaundice appears in the first 24 hours of life; if the bilirubin falls in the high or high-intermediate risk zone; if the baby feeds poorly, is unusually sleepy or hard to wake, has a high-pitched cry, or has dark urine or pale stools; or if yellow color spreads to the arms and legs. When in doubt, call sooner rather than later — only a clinician can examine the baby.
Does a low-risk result mean no follow-up is needed?
No. A low-risk result means the bilirubin is below the 40th percentile for the baby’s age in hours — in the original study none of those newborns later exceeded the 95th percentile — but routine follow-up at 3–5 days of age is still recommended, and any worsening jaundice needs re-evaluation. This tool cannot examine the baby and cannot replace a clinician’s judgment.
Is transcutaneous bilirubin (TcB) the same as serum bilirubin (TSB)?
No. TcB is a painless skin measurement used for screening; TSB is measured from a blood sample and is the reference standard for clinical decisions. TcB estimates TSB within about 2–3 mg/dL and is less reliable above 15 mg/dL or during phototherapy. If you enter a TcB value, treat the result as a screening estimate and confirm it with a clinician.
What changed in the AAP 2022 guideline?
The 2022 AAP clinical practice guideline revision kept hour-specific bilirubin assessment but moved to an updated nomogram by Bahr and colleagues (2021, co-authored by Bhutani), built from nearly 400,000 newborns, with risk assessment tied to gestational age and neurotoxicity risk factors. This calculator implements the classic 1999 Bhutani percentile zones (40th/75th/95th) as the screening reference; the 2022 treatment thresholds are a separate clinical step that your pediatrician applies.
What are the limitations of this tool?
The percentile lines are reconstructed from published anchors of the 1999 nomogram figure (see the methodology section), not from the original dataset, and the tool covers 0–144 hours only without extrapolation. It does not account for hemolysis, albumin level, or the baby’s clinical course, and it does not give treatment advice. It is an educational screening aid — not medical advice, and not a substitute for pediatric evaluation.
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