Guideline 10.1 — Neonatal Hyperbilirubinemia

BEDSIDE ACTION BOX

Jaundice in the first 24 hours is always pathological — measure a serum bilirubin urgently and investigate (haemolysis until proven otherwise).
Measure bilirubin (TcB screen; confirm with serum/TSB when at/near threshold) and plot it against the infant's gestational age and age in hours on the AAP 2022 / NICE threshold chart.
Start intensive phototherapy at/above the phototherapy line; recheck TSB and check the exchange-transfusion line.
Look for signs of acute bilirubin encephalopathy (lethargy, hypotonia, poor feeding → hypertonia, retrocollis/opisthotonus, high-pitched cry) — a medical emergency needing immediate escalation and preparation for exchange transfusion.
Always check a conjugated (direct) bilirubin in prolonged jaundice (>14 days term, >21 days preterm) — conjugated >25 μmol/L (or >20% of total) means investigate for biliary atresia and other cholestasis.

1. Overview

Overview

Neonatal jaundice is very common and usually benign, reflecting physiological immaturity of bilirubin conjugation and increased red-cell turnover. The aim of management is to identify the minority at risk of severe unconjugated hyperbilirubinaemia — which can cross the blood–brain barrier and cause acute bilirubin encephalopathy and permanent kernicterus — and to treat them promptly with phototherapy or, rarely, exchange transfusion, while separately identifying conjugated (cholestatic) jaundice that signals underlying liver/biliary disease.

Why This Topic Matters

Kernicterus is preventable. Systematic screening, correct use of gestational-age-specific thresholds, timely phototherapy, and never missing conjugated hyperbilirubinaemia (biliary atresia is time-critical — best outcomes with Kasai portoenterostomy before ~8 weeks) are the highest-yield safeguards.

2. Who This Guideline Applies To

Scope

All neonates (term and preterm) with visible jaundice, risk factors for hyperbilirubinaemia, or prolonged jaundice.
Infants being screened predischarge and those readmitted for jaundice.
Cross-references: haemolytic disease/anaemia (10.2), sepsis (8.1/8.2), and metabolic/liver disease pathways.

3. Key Definitions

Term	Definition
TSB	Total serum bilirubin.
TcB	Transcutaneous bilirubin (screening; confirm with TSB near thresholds or if >250 μmol/L / after phototherapy).
Unconjugated (indirect)	Fat-soluble, neurotoxic; the fraction phototherapy treats.
Conjugated (direct)	>25 μmol/L or >20% of total → cholestasis; never normal, always investigate.
Physiological jaundice	Appears after 24 h, peaks ~day 3–5, resolves within ~1–2 weeks.
Prolonged jaundice	>14 days (term) or >21 days (preterm).
ABE / Kernicterus	Acute bilirubin encephalopathy / chronic bilirubin encephalopathy (permanent).

4. Initial Assessment

History & Examination

Timing: jaundice <24 h → pathological (haemolysis, sepsis). Peak day 3–5 → usually physiological.
Risk factors: prematurity/late-preterm, blood-group incompatibility (Rh/ABO), G6PD deficiency, previous sibling needing phototherapy, cephalohaematoma/bruising, exclusive breastfeeding with weight loss, East-Asian ancestry.
Examine: extent of jaundice (cephalocaudal progression is unreliable for level — measure), hydration/weight, pallor, hepatosplenomegaly, neurological signs, and stool/urine colour (pale stool + dark urine → cholestasis).
Never estimate severity by eye alone — always measure bilirubin.

5. Causes by Pattern

Pattern	Common causes
<24 h (always pathological)	Haemolysis — Rh/ABO incompatibility, G6PD deficiency, hereditary spherocytosis; congenital infection; sepsis.
Day 2–14 (unconjugated)	Physiological, breastfeeding (suboptimal intake) jaundice, haemolysis, cephalohaematoma/bruising, polycythaemia, sepsis.
Prolonged unconjugated	Breast-milk jaundice, hypothyroidism, ongoing haemolysis, Gilbert/Crigler-Najjar, UTI.
Conjugated (any time)	Biliary atresia, choledochal cyst, neonatal hepatitis, TPN cholestasis, metabolic (galactosaemia, α1-antitrypsin), infection.

6. Investigations

Guided by Timing & Severity

All significant/early jaundice: TSB (with conjugated fraction), blood group + DAT (Coombs) for mother and baby, FBC + film + reticulocytes, G6PD (especially in at-risk ancestry).
Consider sepsis screen if unwell; blood group/antibody status.
Prolonged jaundice: split (conjugated/unconjugated) bilirubin, thyroid function (part of newborn screen), FBC/film, and — if conjugated raised — LFTs, coagulation, urine for reducing substances/culture, and urgent referral for cholestasis work-up (including biliary atresia).

7. Management Algorithm

Jaundice <24 h?

Yes → urgent TSB + haemolysis screen; treat as pathological. No → continue.

Measure & plot

TcB to screen; TSB to confirm near thresholds. Plot on the AAP 2022 / NICE chart for the infant's gestational age and age in hours (account for hyperbilirubinaemia neurotoxicity risk factors).

At/above phototherapy line?

Yes → start phototherapy; support feeding/hydration; recheck TSB (e.g., 4–6 h then per trend). No → routine care + follow-up based on the margin below the line.

Rising toward / at exchange line?

Escalate to intensive multiple phototherapy; give IVIG for isoimmune haemolysis if TSB rises despite intensive phototherapy or is close to exchange; prepare for exchange transfusion.

Signs of ABE?

Emergency — immediate intensive phototherapy and urgent exchange transfusion regardless of the level; involve senior/NICU.

Check the conjugated fraction

Conjugated >25 μmol/L (or >20% total) → cholestasis pathway; refer urgently to exclude biliary atresia (phototherapy does NOT treat conjugated jaundice).

8. Treatment Thresholds

Use the Chart — Not a Single Number

Phototherapy and exchange thresholds depend on gestational age, age in hours, and neurotoxicity risk factors (isoimmune haemolysis, G6PD deficiency, sepsis, albumin <30 g/L, clinical instability). Always plot the measured bilirubin on the official AAP 2022 (US) or NICE (UK) threshold chart for the individual infant. The values below are illustrative anchors only.

Illustrative Anchors (Verify on the Official Chart)

Thresholds rise with gestational age and age in hours, and are lowered by neurotoxicity risk factors. These are orientation values, not prescriptions.

Situation	Principle
Higher gestational age	Higher (more permissive) thresholds.
Lower gestational age / preterm	Lower thresholds — treat earlier.
Neurotoxicity risk factors present	Use the lower ("risk factors") threshold line.
Age in hours	Thresholds increase with postnatal age over the first days.
Approaching exchange line	Escalate to intensive phototherapy ± IVIG; prepare exchange.

⚠ Verify

Do not use fixed numeric cut-offs from memory. Exact μmol/L (or mg/dL) thresholds must be read from the current AAP 2022 / NICE threshold graphs for the specific gestational age, hour of life, and risk profile. Flagged for expert review.

9. Phototherapy

How to Deliver It Well

Use effective blue-light (~460–490 nm) phototherapy; maximise exposed skin surface area and keep an appropriate irradiance/distance; "intensive" = higher irradiance ± multiple sources for levels near exchange.
Protect the eyes; monitor temperature and hydration; support feeding (breastfeeding usually continues) — treat dehydration/poor intake.
Recheck TSB to confirm response and check against the exchange line; stop when TSB falls a safe margin below the phototherapy threshold, then check for rebound as indicated.
Phototherapy treats unconjugated bilirubin only — it is not for conjugated (cholestatic) jaundice (risk of "bronze baby").

10. Exchange Transfusion & IVIG

For Severe / Refractory Hyperbilirubinaemia

Exchange transfusion when TSB is at/above the exchange line despite intensive phototherapy, or at any sign of acute bilirubin encephalopathy — removes bilirubin and antibody-coated red cells. A NICU procedure with defined monitoring (electrolytes, calcium, glucose, platelets) and recognised risks.
IVIG in isoimmune haemolytic disease (Rh/ABO) if TSB continues to rise despite intensive phototherapy or is within a defined margin of the exchange threshold — can reduce the need for exchange.
Correct anaemia and treat the underlying cause; ensure adequate hydration.

11. Conjugated (Cholestatic) Jaundice

Never Miss Biliary Atresia

Conjugated bilirubin >25 μmol/L (or >20% of total) is never physiological — investigate urgently.
Red flags: pale/acholic stools, dark urine, prolonged jaundice, bleeding (vitamin-K-dependent coagulopathy).
Biliary atresia is time-critical — Kasai portoenterostomy has the best outcomes before ~8 weeks of age; refer to a specialist hepatology centre without delay.
Work-up: split bilirubin, LFTs, coagulation, infection/metabolic screen (galactosaemia, α1-antitrypsin), ultrasound, and specialist-directed tests.

12. Monitoring

Parameter	Frequency	Action
TSB trend vs thresholds	Per response (e.g., 4–6 h after starting, then per trend)	Escalate if rising toward exchange line.
Hydration / weight / feeding	Ongoing	Support intake; correct dehydration.
Temperature (on phototherapy)	Regular	Avoid over/underheating.
Neurological status	Continuous clinical vigilance	Any ABE sign → emergency escalation.
Rebound bilirubin	After stopping phototherapy (as indicated)	Recheck, especially haemolysis/preterm.
Conjugated fraction (prolonged)	At prolonged-jaundice review	Raised → cholestasis pathway.

13. Contraindications & Precautions

Safety Cautions

Do not use phototherapy for conjugated hyperbilirubinaemia (ineffective; "bronze baby syndrome").
Do not rely on visual estimation or a single memorised cut-off — always measure and plot on the correct chart.
TcB is a screen; confirm with TSB near thresholds, after phototherapy, or at high levels.
Account for neurotoxicity risk factors — they lower the treatment threshold.
Never delay treatment or referral in early (<24 h) jaundice or suspected cholestasis.

14. Escalation & Parent Counselling

Escalate When…

Any sign of acute bilirubin encephalopathy — emergency, prepare for exchange transfusion.
TSB at/near the exchange line, or rising despite intensive phototherapy — senior/NICU input, IVIG for isoimmune disease.
Conjugated hyperbilirubinaemia — urgent hepatology referral (biliary atresia).

Parent Counselling Points

"Jaundice is very common and usually harmless, but we measure the level with a blood or skin test to be sure it stays safe."
"Phototherapy — special blue light — helps the body clear the bilirubin; you can usually keep feeding, and eye protection is used."
"Watch for jaundice that lasts beyond two weeks, pale poo, or dark wee, and tell us — these need extra checks."

15. Key Pearls

High-Value Clinical Pearls

Jaundice <24 h = pathological (haemolysis) until proven otherwise.
Always plot bilirubin on the gestational-age/hour-specific AAP 2022 / NICE chart; risk factors lower the threshold.
Phototherapy treats unconjugated bilirubin only; check the conjugated fraction in prolonged jaundice.
Conjugated >25 μmol/L (or >20%) → urgent cholestasis work-up; biliary atresia needs Kasai before ~8 weeks.
IVIG can reduce the need for exchange in isoimmune haemolysis.
Signs of ABE (hypotonia→hypertonia, retrocollis, high-pitched cry) → emergency exchange.

16. Common Mistakes to Avoid

Mistake	Why it harms	Better practice
Estimating severity by eye.	Under-treatment / kernicterus.	Measure and plot bilirubin.
Using one fixed cut-off.	Wrong threshold for GA/age.	Use the GA/hour-specific chart with risk factors.
Ignoring <24 h jaundice.	Misses haemolysis.	Urgent TSB + haemolysis screen.
Not checking conjugated fraction.	Misses biliary atresia.	Split bilirubin in prolonged jaundice.
Phototherapy for conjugated jaundice.	Ineffective; bronze baby.	Refer for cholestasis work-up.
Stopping phototherapy without rebound check.	Missed rebound (haemolysis/preterm).	Recheck TSB as indicated.

17. Board-Style High-Yield Summary

Key Takeaways

Jaundice <24 h is pathological → screen for haemolysis (Rh/ABO, G6PD, spherocytosis) and sepsis.
Manage with the AAP 2022 / NICE gestational-age- and hour-specific threshold charts; risk factors lower thresholds.
Phototherapy first-line for unconjugated hyperbilirubinaemia; intensive + IVIG (isoimmune) as levels approach exchange.
Exchange transfusion for TSB at/above the exchange line or any ABE.
Conjugated >25 μmol/L (or >20%) is never normal → urgent cholestasis/biliary-atresia work-up (Kasai before ~8 weeks).
Check the conjugated fraction in all prolonged jaundice (>14 d term, >21 d preterm).

18. References

1.Kemper AR, et al. Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant ≥35 Weeks. AAP. Pediatrics. 2022. https://doi.org/10.1542/peds.2022-058859
2.NICE CG98. Jaundice in newborn babies under 28 days. https://www.nice.org.uk/guidance/cg98
3.Bedside Clinical Guidelines Partnership / West Midlands Neonatal ODN. Jaundice. Neonatal Guidelines 2025–28.
4.Baylor College of Medicine. Guidelines for Acute Care of the Neonate, Ed. 33, 2025–2026.
5.NICE NG hepatology / NASPGHAN. Evaluation of cholestatic jaundice in infants — biliary atresia. https://www.naspghan.org/

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Chapter 10.1 — Neonatal Hyperbilirubinemia