Newborn Bilirubin Calculator (AAP 2022)
Enter gestational age, age in hours and a TSB or TcB value to get the AAP 2022 phototherapy, escalation-of-care and exchange transfusion thresholds for babies born at 35 weeks or later. Below the treatment line, it gives the AAP follow-up interval; it also flags a rapid rate of rise and TcB values that need a serum check.
How to use the bilirubin calculator
- Gestational age. Pick completed weeks at birth. The curves start at 35 weeks; 40 weeks or more share one curve.
- Age in hours. Use the exact age when the sample was drawn, or enter birth and sample times. The same value can need a different action at 18, 48 and 96 hours.
- Bilirubin. Enter the TSB or TcB in mg/dL or µmol/L and tick TcB if it is transcutaneous.
- Neurotoxicity risk factors. Tick any that apply; they switch to the lower curves.
- Optional. Add an earlier value to check the rate of rise, and note hyperbilirubinemia risk factors for follow-up planning.
Reading the result
| Result | What it means |
|---|---|
| Phototherapy threshold | At or above it, phototherapy is indicated. |
| Distance below the threshold | Sets when to measure again (see follow-up below). |
| Escalation of care | Within 2 mg/dL of the exchange threshold: urgent escalation. |
| Exchange transfusion threshold | At or above it, exchange transfusion is recommended. |
| TcB check | Shown when a TcB needs a serum bilirubin to confirm it. |
AAP 2022 phototherapy thresholds by age
The phototherapy threshold rises over the first days of life, is higher for babies born later, and is lower when a neurotoxicity risk factor is present. Values at four common ages:
| Gestational age | 24 h | 48 h | 72 h | 96 h |
|---|---|---|---|---|
| No neurotoxicity risk factors | ||||
| 35 weeks | 10.6 | 14.2 | 16.8 | 18.6 |
| 36 weeks | 11.2 | 14.8 | 17.5 | 19.3 |
| 37 weeks | 11.7 | 15.4 | 18.1 | 20.0 |
| 38 weeks | 12.3 | 16.0 | 18.8 | 20.7 |
| 39 weeks | 12.8 | 16.6 | 19.5 | 21.5 |
| 40+ weeks | 13.3 | 17.0 | 19.8 | 21.8 |
| One or more neurotoxicity risk factors | ||||
| 35 weeks | 8.9 | 12.2 | 14.6 | 16.1 |
| 36 weeks | 9.4 | 12.8 | 15.4 | 17.0 |
| 37 weeks | 10.0 | 13.5 | 16.1 | 17.9 |
| 38+ weeks | 10.5 | 14.0 | 16.6 | 18.2 |
Total serum bilirubin in mg/dL. Use the calculator for the exact hour of life.
Use the total bilirubin; do not subtract the direct (conjugated) fraction. In severe hyperbilirubinemia where the direct or conjugated bilirubin is more than half of the total, consult an expert. A raised direct or conjugated bilirubin at any level needs separate evaluation for cholestasis; these thresholds do not address it.
Once phototherapy is needed
- In hospital, measure the TSB (not TcB) within 12 hours of starting phototherapy, then as often as the baby's age, risk factors, TSB level and trend require.
- Check a hemoglobin, hematocrit or CBC. Send a DAT if the mother is blood group O, Rh(D)-negative, or had a positive antibody screen.
- A baby under 24 hours old at or above the threshold probably has hemolytic disease. Measure G6PD activity if the cause is unknown and the TSB rises despite intensive phototherapy, rises suddenly or after an initial fall, or needs escalation of care.
- Phototherapy can stop once the TSB is at least 2 mg/dL below the hour-specific threshold at which it was started. Continuing longer is an option with rebound risk factors: under 38 weeks, under 48 hours at the start, or hemolytic disease.
When home phototherapy is an option
All of these must be true; otherwise phototherapy is given in hospital.
- Gestational age 38 weeks or more and age 48 hours or more.
- Already discharged, clinically well, feeding well, and no neurotoxicity risk factors.
- No previous phototherapy, and TSB less than 1 mg/dL above the phototherapy threshold (at 1 mg/dL or more above, AAP 2022 advises inpatient phototherapy).
- An LED home phototherapy device is available without delay, and TSB can be measured daily.
On home phototherapy, measure the TSB daily. Admit for inpatient phototherapy if the TSB rises and the gap to the threshold narrows, or if the TSB is 1 mg/dL or more above the threshold.
After phototherapy: checking for rebound
- Treated during the birth hospitalization, and phototherapy started before 48 hours, a positive DAT, or known or suspected hemolytic disease: TSB 6–12 hours after stopping, and a repeat bilirubin the day after stopping.
- Any other baby treated during the birth hospitalization: bilirubin the day after stopping.
- Treated in hospital at birth and readmitted for phototherapy: bilirubin the day after stopping.
- Readmitted without phototherapy at birth, or treated at home: bilirubin or a clinical visit 1–2 days after stopping. Weigh the TSB at stopping against the threshold, gestational age under 38 weeks, feeding and weight gain, and other risk factors.
A TcB can replace the TSB once phototherapy has been off for at least 24 hours.
Escalation of care and exchange transfusion
Escalation of care starts when the TSB is within 2 mg/dL of the exchange transfusion threshold. It means intensive phototherapy (ideally in a NICU), IV fluids, a TSB at least every 2 hours, urgent neonatology consultation or transfer to a unit that can perform an exchange transfusion, and STAT total and direct bilirubin, albumin, CBC, chemistries, and type and crossmatch. For isoimmune hemolytic disease (positive DAT), IVIG 0.5–1 g/kg over 2 hours may be given at this point and repeated in 12 hours; its benefit is uncertain.
The lower exchange curves apply when a neurotoxicity risk factor is present, and also when the TSB keeps rising despite phototherapy.
An urgent exchange transfusion is recommended when the TSB reaches the exchange threshold, and at any bilirubin level if the baby shows signs of intermediate or advanced acute bilirubin encephalopathy (hypertonia, arching, retrocollis, opisthotonos, a high-pitched cry, or recurrent apnea). If a repeat TSB taken while preparing is below the exchange threshold and there are no such signs, the exchange may be deferred while continuing intensive phototherapy and measuring the TSB every 2 hours until it is below the escalation-of-care threshold.
An exchange can also be considered on the bilirubin-to-albumin ratio (TSB in mg/dL divided by albumin in g/dL): 8.0 or more at 38 weeks or later with no neurotoxicity risk factor; 7.2 or more at 38 weeks or later with a risk factor, or at 35–37 weeks with no risk factor other than gestational age; 6.8 or more at 35–37 weeks with at least one other risk factor. The ratio is used alongside the TSB, not instead of it.
| Gestational age | 24 h | 48 h | 72 h | 96 h |
|---|---|---|---|---|
| No neurotoxicity risk factors | ||||
| 35 weeks | 17.9 | 20.7 | 22.9 | 24.5 |
| 36 weeks | 19.1 | 21.9 | 24.1 | 25.5 |
| 37 weeks | 20.3 | 23.1 | 25.2 | 26.6 |
| 38+ weeks | 21.4 | 24.0 | 25.9 | 27.0 |
| One or more neurotoxicity risk factors | ||||
| 35 weeks | 16.1 | 18.5 | 20.1 | 21.1 |
| 36 weeks | 16.6 | 19.1 | 20.9 | 22.1 |
| 37 weeks | 17.2 | 19.7 | 21.7 | 23.1 |
| 38+ weeks | 17.7 | 20.1 | 22.1 | 23.5 |
Total serum bilirubin in mg/dL. Use the calculator for the exact hour of life.
Two kinds of risk factor
Neurotoxicity risk factors (lower the thresholds)
- Gestational age under 38 weeks (built into each gestational-age curve).
- Isoimmune hemolytic disease (positive DAT), G6PD deficiency, or another hemolytic condition.
- Sepsis.
- Albumin below 3.0 g/dL.
- Significant clinical instability in the previous 24 hours.
Hyperbilirubinemia risk factors (shorten follow-up)
These raise the chance of reaching the treatment line later. They do not change the thresholds; use them to choose the shorter end of each follow-up range.
- Lower gestational age (the risk rises with each week below 40 weeks), and jaundice in the first 24 hours.
- A predischarge TSB or TcB close to the phototherapy threshold.
- Hemolysis from any cause, if known, or suspected from a rapid rate of rise.
- Phototherapy before discharge, or a parent or sibling who needed phototherapy or exchange transfusion.
- Family history or ancestry suggesting an inherited red-cell disorder, including G6PD deficiency.
- Exclusive breastfeeding with suboptimal intake.
- Scalp hematoma or significant bruising, Down syndrome, or a macrosomic infant of a diabetic mother.
TcB or TSB?
Transcutaneous bilirubin (TcB) is a screening measurement; treatment decisions use total serum bilirubin (TSB). Measure a TSB when the TcB is above the phototherapy threshold, within 3 mg/dL of it, or 15 mg/dL or higher. During phototherapy, use TSB, not TcB; TcB under phototherapy underestimates the TSB.
Follow-up when the bilirubin is below the threshold
AAP 2022 bases follow-up on how far the bilirubin is below the phototherapy threshold, not on Bhutani risk zones. The intervals apply from 12 hours of age to babies who have not had phototherapy; after phototherapy, use the rebound checks above.
| Below the threshold by | Next step |
|---|---|
| 0.1–1.9 mg/dL | Under 24 hours: delay discharge, consider phototherapy, TSB in 4–8 hours. From 24 hours: TSB in 4–24 hours, and either delay discharge and consider phototherapy, discharge with home phototherapy if all the AAP home phototherapy criteria are met, or discharge without phototherapy with close follow-up. |
| 2.0–3.4 mg/dL | TSB or TcB in 4–24 hours. |
| 3.5–5.4 mg/dL | TSB or TcB in 1–2 days. |
| 5.5–6.9 mg/dL | Discharged under 72 hours: follow-up within 2 days, with TcB or TSB by clinical judgment. From 72 hours: clinical judgment (examination, risk factors, feeding, weight trajectory, family support). |
| 7.0 mg/dL or more | Discharged under 72 hours: follow-up within 3 days, with TcB or TSB by clinical judgment. From 72 hours: clinical judgment (examination, risk factors, feeding, weight trajectory, family support). |
AAP 2022 gives no interval for a bilirubin measured before 12 hours. Every baby needs a TcB or TSB between 24 and 48 hours, or before discharge if earlier, and a baby discharged before 12 hours needs one between 24 and 48 hours. If the recommended outpatient bilirubin cannot be arranged, discharge may be delayed.
Once a TcB or TSB has fallen on its own (not during or after phototherapy) over at least 6 hours, further bilirubin measurements are usually not needed unless jaundice worsens or the baby becomes unwell. The routine newborn follow-up visit still applies.
At each follow-up, check feeding, weight change, stools and hydration, and give parents a clear plan for when to come back.
Rate of rise and hemolysis
A rise of 0.3 mg/dL per hour or more in the first 24 hours, or 0.2 mg/dL per hour or more after that, suggests hemolysis; AAP 2022 advises a DAT if one has not been done. Enter an earlier value in step 4 and the calculator works out the rate and flags it. A hemolytic condition, once identified, is a neurotoxicity risk factor, so the lower thresholds apply.
Worked examples
38 weeks, 48 hours, TSB 13.0 mg/dL, no risk factors
- Phototherapy threshold 16.0 mg/dL, so the value is 3.0 mg/dL below it.
- TSB or TcB in 4–24 hours.
36 weeks, 30 hours, TSB 12.0 mg/dL, positive DAT
- Phototherapy threshold 10.4 mg/dL, so phototherapy is indicated.
- Phototherapy is indicated: start inpatient phototherapy and support feeding and hydration.
- In hospital, measure TSB (not TcB) within 12 hours of starting phototherapy, then as often as the age, risk factors, TSB level and trend require. Phototherapy can stop once the TSB is at least 2 mg/dL below the hour-specific threshold at which it was started; continuing longer is an option with rebound risk factors (under 38 weeks, under 48 hours at the start, or hemolytic disease).
39 weeks, 20 hours, TcB 10.5 mg/dL, no risk factors
- Phototherapy threshold 12.1 mg/dL, so the value is 1.6 mg/dL below it.
- Measure a TSB now. Treatment decisions are based on TSB, not TcB.
- Apply the thresholds and follow-up to the TSB result.
- TcB exceeds or is within 3 mg/dL of the phototherapy threshold, or is 15 mg/dL or higher: measure a TSB now.
37 weeks, TSB 10.0 mg/dL at 20 hours then 13.5 mg/dL at 30 hours
- Phototherapy threshold 12.7 mg/dL, so phototherapy is indicated.
- Phototherapy is indicated: start inpatient phototherapy and support feeding and hydration.
- In hospital, measure TSB (not TcB) within 12 hours of starting phototherapy, then as often as the age, risk factors, TSB level and trend require. Phototherapy can stop once the TSB is at least 2 mg/dL below the hour-specific threshold at which it was started; continuing longer is an option with rebound risk factors (under 38 weeks, under 48 hours at the start, or hemolytic disease).
- Rate of rise 0.35 mg/dL per hour, which meets the rapid-rise cutoff and suggests hemolysis: send a DAT if not already done, and use the neurotoxicity curves if a hemolytic condition is identified.
For parents: what the bilirubin number means
Most newborns look a little yellow in the first week. Doctors compare the bilirubin with a line for your baby's age in hours, so the same number can be fine on day 4 and need treatment on day 1. For a healthy baby born at 40 weeks, the treatment line is about 13.3 mg/dL at 24 hours and about 21.8 mg/dL at 4 days.
Call your baby's doctor right away if the yellow color appears in the first 24 hours.
Call your baby's doctor the same day if
- The yellow color spreads to the belly, arms or legs, or the whites of the eyes turn yellow.
- Your baby is hard to wake, feeding poorly, or has fewer wet or dirty diapers.
- Stools are pale or chalky, or urine is dark.
- The yellow color lasts beyond 2 weeks in a formula-fed baby or 3 weeks in a breastfed baby.
Get emergency care if your baby is very hard to wake, unusually floppy or stiff, not feeding at all, has a high-pitched cry, or arches the neck or back. Breastfeeding at least 8 to 12 times a day in the first days helps clear bilirubin. Do not put your baby in sunlight or give water or sugar water to treat jaundice; if treatment is needed, it is usually phototherapy. More from HealthyChildren.org.
What changed from the 2004 guideline
AAP 2022 raised the phototherapy thresholds, added gestational-age-specific curves from 35 to 40 weeks, defined an escalation-of-care zone, and replaced risk-zone follow-up with follow-up based on the distance below the threshold. Compare the 2004 and 2022 guidelines.
Frequently asked questions
There is no single number. The treatment line depends on the baby's age in hours, gestational age and risk factors. For a healthy baby born at 40 weeks or later, the AAP 2022 phototherapy threshold is about 13.3 mg/dL at 24 hours and about 21.8 mg/dL at 96 hours. Babies born earlier or with risk factors have lower thresholds.
AAP 2022 publishes hour-by-hour threshold curves for each gestational age from 35 weeks, with a lower set of curves when a neurotoxicity risk factor is present. The calculator looks up the curve for the baby's gestational age and risk status and reads the threshold at the exact age in hours.
Newborn infants born at 35 weeks of gestation or later. Infants born before 35 weeks need NICU-specific guidance.
Measure a TSB when the TcB is above the phototherapy threshold, within 3 mg/dL of it, or 15 mg/dL or higher. Treatment decisions are based on TSB.
Neurotoxicity risk factors: isoimmune hemolytic disease (positive DAT), G6PD deficiency or another hemolytic condition, sepsis, albumin below 3.0 g/dL, and significant clinical instability in the previous 24 hours. Gestational age under 38 weeks is also a risk factor, and it is built into each gestational-age curve.
A rise of 0.3 mg/dL per hour or more in the first 24 hours, or 0.2 mg/dL per hour or more after that, suggests hemolysis. AAP 2022 advises a DAT if one has not been done.
AAP 2022 replaced risk-zone follow-up from the Bhutani nomogram with follow-up based on how far the bilirubin is below the phototherapy threshold. The nomogram is still useful background for reading older notes.
Methods and data
Thresholds are the hour-by-hour values from the AAP 2022 supplemental tables for each gestational age and risk group. Like the tables, the calculator uses completed hours of age: at 24 hours 50 minutes it reads the 24-hour value. Gestational ages above the last published curve use that curve (for example, 39 weeks with a risk factor uses the 38+ week curve), and the value stays level after the curve ends. Escalation of care is the exchange threshold minus 2 mg/dL; 1 mg/dL = 17.1 µmol/L.
Threshold data: AAP 2022 Clinical Practice Guideline (Kemper et al., Pediatrics 150(3):e2022058859), Supplemental Tables 1-4 (version 1.0.0).
References
- Kemper AR, Newman TB, Slaughter JL, et al. Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation. Pediatrics. 2022;150(3):e2022058859. doi.org/10.1542/peds.2022-058859
- American Academy of Pediatrics Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004;114(1):297-316. doi.org/10.1542/peds.114.1.297
- Bhutani VK, Johnson L, Sivieri EM. Predictive ability of a predischarge hour-specific serum bilirubin for subsequent significant hyperbilirubinemia in healthy term and near-term newborns. Pediatrics. 1999;103(1):6-14. doi.org/10.1542/peds.103.1.6
- Jaundice in Newborns (parent information) www.healthychildren.org/English/ages-stages/baby/Pages/Jaundice.aspx
- Hyperbilirubinemia clinical resources www.aap.org/en/patient-care/hyperbilirubinemia/