The Bhutani Nomogram (hour-specific bilirubin nomogram) is a validated tool for predicting the risk of significant hyperbilirubinemia in newborns โฅ35 weeks gestation. It plots the total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) against the postnatal age in hours to assign a risk zone. Combined with neurotoxicity risk factors, it guides decisions on phototherapy and exchange transfusion thresholds per the updated AAP 2022 guidelines.
๐ก Key Update (AAP 2022): The 2022 AAP guidelines introduced gestational age-specific and neurotoxicity risk factor-specific thresholds, replacing the older single-threshold approach. This calculator incorporates these updated tiered thresholds.
๐ Bhutani Nomogram Risk Zone Assessment
Used to calculate exact postnatal age in hours
Time blood was drawn or TcB measured
Or transcutaneous bilirubin (TcB) value
Must be โฅ35 weeks for this nomogram
โ
Postnatal Age
โ
โ ๏ธ Neurotoxicity Risk Factors (Check all that apply)
๐ AAP 2022: All newborns discharged before 72 hours must have a follow-up plan based on their predischarge bilirubin risk zone and risk factors.
๐ Bhutani Nomogram โ Risk Zone Thresholds (mg/dL)
Age (hrs)
Low Risk (<)
Low-Intermediate
High-Intermediate
High Risk (โฅ)
Values represent 40th, 75th, and 95th percentile TSB thresholds. Based on Bhutani et al. 1999 (n=2,840 newborns โฅ36 weeks).
๐ก AAP 2022 Phototherapy Thresholds by GA & Age
GA (wks)
24h
48h
72h
96h
โฅ120h
35
7.0
9.0
11.0
12.0
12.5
36
8.0
10.5
12.5
13.5
14.0
37
9.0
11.5
13.5
14.5
15.0
38
10.0
12.5
14.5
15.5
16.0
39
11.0
13.5
15.5
16.5
17.0
โฅ40
12.0
14.5
16.5
17.5
18.0
Values in mg/dL for LOW-RISK infants. Subtract 2 mg/dL for medium risk; subtract 3 mg/dL for high risk (major neurotoxicity risk factors). AAP 2022 guidelines.
๐ Clinical Guidance
Phototherapy Principles
Intensive phototherapy: Irradiance โฅ30 ยตW/cmยฒ/nm; use bili blanket + overhead lights for maximum effect.
Eye protection: Always shield eyes during phototherapy. Remove for feeding.
Hydration: Increase feeds by 10โ20%; monitor weight and urine output. IV fluids if poor oral intake.
Discontinue PT: When TSB falls โฅ2 mg/dL below threshold and infant โฅ48 hrs old. Recheck TSB 12โ24 hrs after stopping.
TcB monitoring: TcB is reliable when <15 mg/dL and no phototherapy. Always confirm with TSB if TcB is elevated or phototherapy has been used.
Neurotoxicity risk factors now formally lower the treatment threshold
TcB can be used for initial screening; confirm with TSB if above threshold
Outpatient phototherapy is an option for stable infants with mild-moderate hyperbilirubinemia
๐ซ Direct (conjugated) bilirubin โฅ1 mg/dL or >20% of TSB: Suggests cholestasis. Do NOT use phototherapy as primary treatment. Evaluate for biliary atresia, neonatal hepatitis, metabolic disorders. Urgent GI/hepatology referral.
๐ References
Bhutani VK, et al. 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.
AAP 2022 Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation. Pediatrics. 2022;150(3):e2022058859.
Maisels MJ, et al. Hyperbilirubinemia in the Newborn Infant โฅ35 Weeks' Gestation: An Update With Clarifications. Pediatrics. 2009;124(4):1193-1198.
Kemper AR, et al. Universal bilirubin screening, guidelines, and evidence. Pediatrics. 2022;150(3):e2022057612.
