About the Newborn Hyperbilirubinemia Assessment
This calculator screens a newborn's jaundice risk using the Bhutani hour-specific bilirubin nomogram, published by Bhutani, Johnson, and Sivieri in 1999. The nomogram was built from serial predischarge total serum bilirubin (TSB) measurements in healthy newborns of at least 35 weeks gestation and at least 2000 g birth weight, plotted against postnatal age in hours. It divides the chart into four percentile-based zones - low risk, low-intermediate risk, high-intermediate risk, and high risk - that predict how likely a newborn is to later develop significant hyperbilirubinemia.
How the calculator works
- The published 40th, 75th, and 95th percentile tracks are interpolated at the entered postnatal age in hours.
- The entered total serum bilirubin is compared against those three thresholds to assign a risk zone: below the 40th percentile is low risk, 40th-75th is low-intermediate, 75th-95th is high-intermediate, and at or above the 95th percentile is high risk.
- An approximate percentile is interpolated between the same anchor points so you can see how close a value sits to the next zone, not just which zone it falls in.
Putting the result in context
The zone is a screening signal, not a treatment threshold. Phototherapy and exchange-transfusion decisions use separate hour-specific and gestational-age-specific curves (for example the American Academy of Pediatrics guideline) and should always be made by the treating clinician using the official charts. Additional neurotoxicity risk factors - isoimmune hemolytic disease, G6PD deficiency, birth asphyxia, sepsis, acidosis, or albumin below 3.0 g/dL - shift a newborn toward closer monitoring and a lower treatment threshold even at the same bilirubin level.
When to consult a professional
This tool performs an approximation of the standard nomogram arithmetic for education and screening support. It does not diagnose hyperbilirubinemia and does not set a phototherapy or exchange-transfusion threshold. Any bilirubin result, especially one in the high-intermediate or high-risk zone, should be reviewed with the newborn's pediatric care team alongside the official nomogram chart and current treatment guidelines.