### Description

Bhutani et al developed curves for predicting the risk of significant hyperbilirubinemia in a newborn infant based on the total serum bilirubin level and the number of hours since birth that the serum specimen was collected. This can help identify those infants who require closer monitoring and who may benefit from aggressive management. The authors are from the Pennsylvania Hospital in Philadelphia.

Patient selection: term or near term infants from 18 to 144 hours after delivery.

Total Serum Bilirubin in mg/dL

Hour Post Delivery

40% Curve

75% Curve

95% Curve

18

4.6

5.6

7.0

24

5.0

6.4

7.8

30

6.0

7.4

9.4

36

7.1

9.0

11.1

42

7.9

10.0

12.4

48

8.6

10.8

13.2

54

9.1

11.7

14.1

60

9.6

12.6

15.2

66

10.5

13.1

15.6

72

11.2

13.4

16.0

78

11.4

14.0

16.3

84

11.6

14.7

16.9

90

12.0

14.9

17.1

96

12.4

15.2

17.4

102

12.6

15.4

17.5

108

12.9

15.5

17.5

114

13.1

15.6

17.6

120

13.2

15.8

17.6

126

13.2

15.6

17.5

132

13.2

15.5

17.5

138

13.2

15.5

17.5

144

13.2

15.5

17.5

from Figure 2, page 9

Using JMP these can be approximated by the following equations:

total serum bilirubin defining the 40th percentile curve =

=  (-0.000706 * ((hours since birth)^2)) + (0.18404 * (hours since birth)) +1.2802

total serum bilirubin defining the 75th percentile curve =

= (0.0000025 * ((hours since birth)^3)) - (0.001604 * ((hours since birth)^2)) + (0.28144 * (hours since birth)) + 0.74945

total serum bilirubin defining the 95th percentile curve =

= (0.0000071 * ((hours since birth)^3)) - (0.002915 * ((hours since birth)^2)) + (0.38946 * (hours since birth)) + 0.4643

Total Serum Bilirubin

Zone

Probability of Significant Hyperbilirubinemia

below 40th percentile curve

low risk

practically 0

from to the 40th to the 75th percentile curve

low intermediate risk

1 in 46

above the 75th to the 95th percentile curve

high intermediate risk

1 in 8

above the 95th percentile curve

high risk

2 in 5

from Table 3, page 11