Table 3.

Predictive Ability of Predischarge TSB in the Percentile-Based Risk Zones for Subsequent Significant Hyperbilirubinemia*

Location of Predictive Predischarge TSB VectorOutcome: Subsequent
Significant
Hyperbilirubinemia
Predictive Ability
Predischarge Hour-specific
TSB Risk Zone
PercentilesTotalPresent (P)*Absent (A)P:A RatioProbability of
Disease
Likelihood Ratio
of Disease
High-risk zone>95th172681042:3 2 /514.08
Upper-intermediate76th–95th356463101:7 1 /83.20
Lower-intermediate40th–75th556125441:451 /460.48
Low-risk zone<40th175601756000
Total284012627141:221 /23
  • * Defined as a subsequent TSB value in the high-risk zone (≥95th percentile track)

  • P:A Ratio: those with significant hyperbilirubinemia (present) to those without (absent).

  • Based on the prevalence of disease in a given population (present/(present + absent); 1/23 in our population). The likelihood ratio may be used to calculate a revised or posttest probability of disease:posttest odds = pretest odds × LR where odds = probability ÷ (1 − probability). Because the LR is prevalence independent, it can be used to calculate the posttest probability at any site. Alternatively, from a clinical perspective, the revised probability may be obtained at any site by dividing the absent component of the present:absent ratio for the total population by the LR to calculate the revised present:absent ratio for each risk zone.