The Bhutani Nomogram Explained: Using It Confidently in Neonatal Practice
The Bhutani nomogram predicts which newborns are at risk for severe hyperbilirubinemia. This guide covers how to plot values, interpret risk zones, and decide on phototherapy — plus how to document it efficiently.
Background: Why the Bhutani Nomogram?
Neonatal hyperbilirubinemia is one of the most common clinical problems in the first week of life. Severe, untreated jaundice can cause kernicterus — permanent neurological damage. The Bhutani hour-specific nomogram, published in Pediatrics in 1999 by Dr. Vinod Bhutani, gives clinicians a reliable, evidence-based tool to identify which newborns need closer follow-up or treatment.
The key insight: bilirubin level is only interpretable in the context of the infant's age in hours. A TSB of 12 mg/dL at 36 hours carries a very different risk than the same level at 96 hours.
Understanding the Nomogram Structure
The Bhutani nomogram plots Total Serum Bilirubin (TSB) in mg/dL (or µmol/L) on the Y-axis against age in hours on the X-axis (from 0 to 168 hours / 7 days).
Four zones are defined by percentile curves:
| Zone | Description | Approximate TSB at 48h |
|---|---|---|
| High Risk | Above 95th percentile | >17 mg/dL |
| High Intermediate Risk | 75th–95th percentile | 13–17 mg/dL |
| Low Intermediate Risk | 40th–75th percentile | 10–13 mg/dL |
| Low Risk | Below 40th percentile | <10 mg/dL |
Step-by-Step: Plotting a Value
- Measure TSB (or transcutaneous bilirubin, TcB) and record the exact age in hours — not days.
- Find the age in hours on the X-axis.
- Move vertically to the TSB value.
- Identify which zone the point falls in.
- Apply risk zone guidance (see below).
Example: A 52-hour-old term infant has TSB of 14.2 mg/dL. Plotting this on the nomogram places it in the High Intermediate Risk zone → warrants intensified phototherapy evaluation.
Risk Zone Decision Guide
Low Risk Zone:
- Discharge is safe if no other risk factors.
- Follow-up at 48–72 hours post-discharge is still recommended by AAP guidelines.
Low Intermediate Risk Zone:
- Consider early follow-up (within 24–48 hours of discharge).
- Educate parents on jaundice signs.
High Intermediate Risk Zone:
- Follow up within 24 hours.
- Consider initiation of phototherapy depending on additional risk factors (prematurity, haemolysis, G6PD deficiency, exclusive breastfeeding, cephalhaematoma, significant bruising).
High Risk Zone:
- Phototherapy indicated.
- Consider hospital admission if rapid rise or near exchange transfusion threshold.
Additional Risk Factors That Lower Your Threshold
The AAP 2022 guidelines emphasise that risk factors modify the threshold for intervention:
- Gestational age 35–37 weeks
- Isoimmune haemolytic disease (ABO, Rh)
- G6PD deficiency
- Asphyxia, lethargy, temperature instability
- Sepsis
- Significant bruising or cephalhaematoma
- Exclusive breastfeeding with poor intake
For infants with these factors, phototherapy should be considered even in the High Intermediate zone.
Transcutaneous Bilirubin (TcB) vs Total Serum Bilirubin (TSB)
TcB is a non-invasive screening tool but has limitations:
- TcB can overestimate TSB after phototherapy exposure
- TcB is less reliable in darker-skinned infants
- Always confirm TcB values above the 75th percentile with a serum TSB before initiating phototherapy
Using the Bhutani Tool in Clinit
Clinit's pediatric module includes a built-in Bhutani nomogram tracker that:
- Accepts TSB (mg/dL or µmol/L) and age in hours
- Automatically plots the value on the nomogram and identifies the risk zone
- Colour-codes the result (green / amber / red) in the patient timeline
- Sends a care team alert when a value plots in the High or High Intermediate zone
- Tracks serial measurements to display the trajectory (rising vs stable)
- Links bilirubin plots directly to the treatment record
Having this embedded in the EMR means you never need to pull out a separate reference chart, and every bilirubin measurement becomes part of the permanent clinical record.