Neonatal & paediatrics
Neonatal bilirubin calculator
The jaundice work-up before the chart: conjugated fraction, unit conversion, rate of rise — with the red flags called out.
A jaundiced neonate with a total bilirubin of 250 µmol/L (14.6 mg/dL), of which 30 µmol/L is conjugated (direct).
Unconjugated 220 µmol/L, conjugated fraction 12% — flagged: conjugated 30 µmol/L is pathological
Even with a fraction under 20%, a conjugated bilirubin above ~17 µmol/L is always pathological (AAP 2022) — in a neonate, biliary atresia must be excluded urgently, alongside sepsis, TORCH infection, and metabolic disease.
Who this is for
For paediatric, neonatal, and primary-care clinicians working up a jaundiced newborn. Fractionates total bilirubin into conjugated and unconjugated, converts between µmol/L and mg/dL, and computes the rate of rise between two samples — flagging the conjugated hyperbilirubinaemia and haemolysis-speed rises that change the work-up entirely.
How it works
What it does
The neonatal jaundice work-up numbers: conjugated (direct) fraction, unit conversion between µmol/L and mg/dL, and the rate of rise between two samples.
Red flags it checks
Conjugated bilirubin above ~17 µmol/L (AAP 2022) or a fraction above 20% is always pathological — in a neonate, biliary atresia must be excluded urgently. Jaundice in the first 24 hours of life, and a rise faster than about 8.5 µmol/L per hour, both point to haemolysis.
Treatment thresholds
Phototherapy and exchange-transfusion thresholds are gestation- and hour-specific: plot the TSB on your unit's chart (AAP 2022 or NICE). Chart-based thresholds are planned for this tool using the official tables.
Built on published evidence
- Phototherapy and exchange thresholds are gestation- and hour-specific — plot TSB on your unit's chart. References: AAP 2022; NICE NG98. Chart-based thresholds are coming to this tool
Codification last reviewed 2026-08-28, and checked against published reference values in automated tests on every release — see the full evidence ledger.
Questions clinicians ask
When is conjugated bilirubin pathological in a neonate?
A conjugated (direct) bilirubin above ~17 µmol/L (1 mg/dL, AAP 2022) or a conjugated fraction above 20% is always pathological — biliary atresia must be excluded urgently, and sepsis, TORCH infection, and metabolic disease belong on the list.
What rate of rise suggests haemolysis?
A rise faster than about 8.5 µmol/L per hour (0.5 mg/dL/h) points to haemolysis — escalate, recheck early, and reassess against the treatment chart. Jaundice appearing within the first 24 hours of life is likewise pathological until proven otherwise.
Does this tell me when to start phototherapy?
No — phototherapy and exchange-transfusion thresholds are gestation- and hour-specific, so plot the total bilirubin on your unit's chart (AAP 2022 or NICE NG98). Chart-based thresholds using the official tables are planned for this tool.
How do I convert bilirubin between units?
1 mg/dL = 17.1 µmol/L. The tool accepts either unit and shows the conversion alongside the result, so values from different laboratories can be compared directly.
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