Neonatal Jaundice Calculator

AAP 2022 reference charts

The Indian Pediatrics 2023 review of the AAP guideline adopts these hour-specific curves for 35 to 40 weeks, and the IAP textbook chapter points to the AAP or NICE charts. I found no separate IAP threshold chart, so the IAP reference chart here is the AAP 2022 chart.

Original figure from the guideline

Redrawn from the guideline's supplemental table

Values in mg/dL are Supplemental Tables 1 to 4 of the guideline (hour-by-hour, 1 to 336 h). Escalation of care starts 2 mg/dL below the exchange line. In the original Figs 5 and 6 the exchange curves are dotted for the first 24 h because of uncertainty.

Preterm, 34 weeks or lower: NICE 2023 phototherapy and exchange cut-offs

Total serum bilirubin (mg/dL) for babies of 34 weeks gestation or lower, at 12, 24, 48 and 72 h or more. The calculator interpolates between these ages.

Source: NICE 2023 guideline, phototherapy and exchange transfusion cut-offs of total serum bilirubin (mg/dL) for babies 34 weeks gestation or lower. Values are given from 12 h; before 12 h the 12 h value is shown as the lowest reference. For 35 weeks and above use the AAP 2022 tab.

NICE term table (38 weeks and above), µmol/L

Rules used by the calculator

Neurotoxicity risk factors (AAP 2022 Table 2)

• Gestational age under 38 weeks (risk rises with prematurity; handled by the separate curves)
• Albumin below 3.0 g/dL
• Isoimmune hemolytic disease (positive DAT), G6PD deficiency, or another hemolytic condition
• Septicemia
• Significant clinical instability in the previous 24 hours

Treatment levels

• Use TSB, not TcB, for treatment decisions. Do not subtract direct bilirubin.
• Start intensive phototherapy at or above the hour-specific threshold. An infant under 24 h with a TSB at or above the threshold likely has a hemolytic process.
• Escalation of care begins at the exchange threshold minus 2 mg/dL: NICU, intensive phototherapy, IV hydration, TSB at least every 2 h, STAT labs including albumin, type and crossmatch.
• Urgent exchange transfusion at or above the exchange threshold, or with signs of intermediate or advanced acute bilirubin encephalopathy at any level.
• Bilirubin to albumin ratio (TSB mg/dL divided by albumin g/dL), exchange may be considered at or above: 8.0 for 38 weeks and above without risk factors; 7.2 for 38 weeks and above with a risk factor, or 35 to 37 weeks without; 6.8 for 35 to 37 weeks with a risk factor.
• IVIG 0.5 to 1 g/kg over 2 h in isoimmune hemolysis (DAT positive) at or above the escalation level; can be repeated in 12 h.

During and after phototherapy (AAP 2022)

• Hospital: TSB within 12 h of starting, then by age, risk factors, level and trend. A TcB under the lights underestimates.
• Stopping is an option when TSB is at least 2 mg/dL below the threshold at the hour phototherapy started. Treat longer if rebound risk: gestational age under 38 weeks, started before 48 h, or hemolytic disease.
• Exceeded the threshold during the birth stay and (phototherapy before 48 h, DAT positive, or hemolysis): TSB 6 to 12 h after stopping and again the next day.
• Other infants treated in the birth stay: bilirubin the next day. Readmitted or home phototherapy: bilirubin or clinical review in 1 to 2 days. Allow at least 12 h, preferably 24 h, after stopping. TcB is acceptable 24 h or more after stopping.
• Home LED phototherapy needs all of: 38 weeks or more, 48 h or more old, clinically well with adequate feeding, no neurotoxicity risk factor, no previous phototherapy, TSB no more than 1 mg/dL above the threshold, a device available without delay, and TSB daily.

Before treatment: follow-up by distance below the threshold (AAP 2022 Figure 7)

Figure 7 applies from 12 h of age, in infants who have not received phototherapy. An infant discharged before 12 h needs a bilirubin between 24 and 48 h.

Screening and hemolysis flags

• TSB or TcB between 24 and 48 h of age, or before discharge if earlier. Jaundice in the first 24 h needs a TcB or TSB as soon as possible.
• Check a TSB if the TcB is 15 mg/dL or more, or within 3 mg/dL of the phototherapy threshold.
• A rise of 0.3 mg/dL/h or more in the first 24 h, or 0.2 mg/dL/h or more after, suggests hemolysis: check DAT.
• Direct bilirubin above 50% of TSB: consult a specialist.

NICE (preterm, and as a comparison for term)

• 38 weeks or more and over 24 h old, below the phototherapy threshold but within 50 µmol/L: repeat bilirubin within 18 h if a sibling needed phototherapy or the mother plans exclusive breastfeeding, otherwise within 24 h. More than 50 µmol/L below: do not routinely repeat.
• During phototherapy: repeat serum bilirubin 4 to 6 h after starting; if stable or falling, every 6 to 12 h.
• Stop phototherapy when bilirubin is at least 50 µmol/L below the threshold. Check for rebound 12 to 18 h after stopping.
• Intensify (multiple phototherapy units) if bilirubin rises faster than 8.5 µmol/L per hour, is within 50 µmol/L of the exchange threshold, or does not fall within 6 h of starting.

AAP Figure 4: approach to escalation of care

Where the numbers come from, and their limits

• AAP values come from Supplemental Tables 1 to 4 in the guideline PDF you supplied (Kemper et al., Pediatrics 2022;150(3):e2022058859), read hour by hour from 1 to 336 h. Hour 0 is not tabulated, so the 1 h value is used. Between whole hours the page interpolates in a straight line.
• The original exchange curves are dotted for the first 24 h because the guideline marks them uncertain.
• The figures shown on the charts tab and here are cropped from the same PDF.
• For 35 to 37 weeks the NICE comparison card uses the NICE phototherapy formula; its exchange level there is an estimate (phototherapy plus 100 µmol/L from 72 h) because NICE publishes it only as graphs.
• The 34-weeks-or-lower cut-offs (23 to 34 weeks, at 12, 24, 48 and 72 h or more) follow the NICE 2023 guideline table, not the AAP 2022 guideline, which covers 35 weeks and above only. Values between listed ages are interpolated; before 12 h the 12 h value is used.
• This is a decision-support aid for clinicians. Confirm treatment decisions against the guideline and your unit protocol.

Sources: AAP 2022 guideline · PediTools bili2022 · Indian Pediatrics, Jan 2023 · IAP textbook chapter · NICE NG98 · MSD Manual, under 35 weeks