Newborn Hyperbilirubinemia Assessment - Bhutani Nomogram and AAP Phototherapy Threshold

A newborn hyperbilirubinemia assessment reads the infant's total serum bilirubin (TSB) against the hour-specific Bhutani nomogram and the AAP 2004 phototherapy and exchange transfusion thresholds, so a caregiver can see the risk zone, the treatment threshold, and the next step in one place. The same form accepts mg/dL or SI micromol/L, picks the correct AAP risk group from gestational age and four neurotoxicity risk factors, and returns a clear Yes or No on phototherapy.

• • Discharge review: A first-time parent bringing a 72-hour-old infant home who wants a structured read of the discharge TSB value.
• • Postpartum handover: A postpartum nurse or midwife running through the same TSB value the pediatric team will see at the next visit.
• • Late preterm with risk factors: A medical student reviewing a clinical vignette in which a 36-week infant has sepsis and a TSB of 12 mg/dL at 48 hours.
• • Resource-limited clinic: A community clinician in a setting where a browser-based hour-by-hour assessment is still available on a phone or tablet.

Use this assessment together with a clinical exam, a feeding review, and a recent serum or transcutaneous bilirubin reading. It does not replace a pediatric exam and it does not interpret conjugated (direct) bilirubin.

When phototherapy is indicated, plan for admission to a unit with blue-light phototherapy. When exchange transfusion is indicated, escalate immediately to a tertiary neonatal unit.

When the same caregiver is reviewing the first hours of life, the Apgar score calculator provides the bedside score that usually sits next to the TSB value on the admission note.

This calculator combines the Bhutani hour-specific bilirubin nomogram with the AAP 2004 phototherapy and exchange transfusion thresholds. The same five inputs feed both reads so the risk zone and the treatment answer come from the same numbers.

• ageHours: Postnatal age in hours when the TSB was drawn.
• tsbMgdl: Total serum bilirubin in mg/dL. SI values in micromol/L are converted at 1 mg/dL = 17.1 micromol/L.
• P40, P75, P95: 40th, 75th, and 95th percentile hour-specific TSB values from the Bhutani nomogram.
• AAP risk group: Lower risk (>=38w, no risk), Medium risk, or Higher risk (35-37w with a risk factor).
• AAPPhotoThreshold: AAP 2004 hour-specific phototherapy threshold (mg/dL) for the assigned risk group.
• AAPExchangeThreshold: AAP 2004 hour-specific exchange transfusion threshold (mg/dL) for the assigned risk group.

The Bhutani nomogram is read by linear interpolation between the two surrounding table hours, and the AAP thresholds are read from the 24, 48, 72, 96 and 120 hour anchor points.

According to Bhutani VK, Johnson L, Sivieri EM, Pediatrics 1999, a predischarge hour-specific total serum bilirubin measurement predicts the subsequent risk of significant hyperbilirubinemia, with values at or above the 95th percentile placing the newborn in the high-risk zone of the nomogram.

According to American Academy of Pediatrics 2004 Hyperbilirubinemia Guideline, phototherapy and exchange transfusion thresholds in healthy term infants are 38 weeks gestation or older, with lower thresholds for infants 35 to 37 weeks gestation or with neurotoxicity risk factors.

The hour-specific TSB thresholds the AAP 2004 guideline uses depend on completed weeks of gestation, and a gestational age calculator helps confirm the same 35-37 week or 38+ week bracket this assessment applies.

Four concepts drive the result.

A TSB of 15 mg/dL on a 96-hour-old term infant and a TSB of 15 mg/dL on a 60-hour-old late preterm infant can both sit above the phototherapy threshold, but the next steps differ. The risk group and the age in hours together drive the next step.

A small-for-gestational-age infant is a related neurotoxicity concern, and a birthweight percentile calculator shows where the same infant sits on the population growth curve used during the same admission.

The form works from a small set of clinical inputs. Each input should be set from a recent exam, a recent lab value, or a clear yes-or-no on a published risk factor.

1. 1 Enter the infant's age in hours: Enter the infant's postnatal age in hours at the time the TSB was drawn (whole integers from 1 to 336).
2. 2 Enter the TSB and pick the unit: Enter the total serum bilirubin in mg/dL or use the micromol/L toggle to enter the SI value. The form converts SI values to mg/dL at 1 mg/dL = 17.1 micromol/L.
3. 3 Pick the completed weeks of gestation: Select the completed weeks of gestation at birth (35-37 weeks for late preterm, 38-40+ weeks for term).
4. 4 Mark the four neurotoxicity risk factors: Select Yes for any risk factor that is present: isoimmune hemolytic disease or G6PD deficiency, sepsis or significant clinical instability, or serum albumin below 3.0 g/dL.
5. 5 Read the result panel: The result panel shows the Bhutani nomogram zone, the AAP risk group, the phototherapy threshold, the exchange transfusion threshold, and a plain-language next step.
6. 6 Share the result with the pediatric team: Write the inputs and the result on the visit note so the next clinician can compare it with their own findings.

A clinician evaluating a 60-hour-old late preterm infant (36 weeks) with isoimmune hemolytic disease and a TSB of 13 mg/dL enters 60 hours, 13 mg/dL, 36 weeks, and Yes for isoimmune hemolytic disease. The result panel returns the High risk zone, the Higher risk group, phototherapy Yes, and the next step to initiate intensive phototherapy and repeat TSB in 4 to 6 hours.

When isoimmune hemolytic disease is the reason a TSB value is rising fast, a IVIG dose calculator returns the weight-based intravenous immunoglobulin dose the pediatric team will order alongside phototherapy.

Using this tool offers several practical advantages over reading a chart in isolation.

• • Nomogram and thresholds in one read: Combines the Bhutani nomogram and the AAP 2004 thresholds in a single read.
• • US and SI units in one form: Uses a units toggle so the same form accepts a US-style mg/dL value or an SI-style micromol/L value.
• • Clear Yes or No on phototherapy and exchange: Flags phototherapy and exchange transfusion as clear Yes or No answers keyed to the AAP risk group.
• • Plain-language next step: Returns a plain-language recommendation for the next TSB recheck interval so the family and the primary care team share the same follow-up plan.
• • Pairs cleanly with the AAP 2022 Kemper update: The same inputs and risk factors still feed the latest hour-specific guidance from the 2022 Kemper update, so the newborn hyperbilirubinemia assessment is not tied to a single guideline revision.

The same tool works for the first-week discharge review, the postpartum ward handover, and the next-clinic follow-up visit. The risk group and the next step stay consistent across visits.

Stable blood pressure is one of the markers the AAP 2004 framework reads into the 'significant clinical instability' risk factor, and a pediatric blood pressure calculator turns the same bedside cuff reading into the age-specific percentile used in the same workup.

The output depends on the TSB value, the age in hours, the gestational age, and the four neurotoxicity risk factors. Four small changes can move the result by a zone or by a treatment threshold.

• • The 2004 AAP hour-specific thresholds apply to infants 35 weeks gestation or older. Infants less than 35 weeks need a separate, lower threshold table and a clinical review by a neonatologist.
• • This tool does not interpret conjugated (direct) bilirubin, which is a different clinical workup that usually points to cholestasis rather than physiologic jaundice.

The result is a screening and triage tool, not a diagnostic test. Always pair the output with a clinical exam, a feeding review, and a recent serum or transcutaneous bilirubin reading.

According to Merck Manual Professional Edition (Dysart K, reviewed 2024), the more preterm the newborn, the lower the threshold bilirubin level for treatment, and operational thresholds have been developed that account for gestational age, postnatal age in hours and additional risk factors for neurotoxicity.

Late preterm infants often leave the hospital before the 120-hour window, and a adjusted age calculator helps the family read the same corrected age when the next TSB is drawn at a follow-up visit.