Location of Predictive Predischarge TSB Vector | Outcome: Subsequent Significant Hyperbilirubinemia | Predictive Ability | |||||
---|---|---|---|---|---|---|---|
Predischarge Hour-specific TSB Risk Zone | Percentiles | Total | Present (P)^{*} | Absent (A) | P:A Ratio^{†} | Probability of Disease | Likelihood Ratio of Disease |
High-risk zone | >95th | 172 | 68 | 104 | 2:3 | 2 /5 | 14.08 |
Upper-intermediate | 76th–95th | 356 | 46 | 310 | 1:7 | 1 /8 | 3.20 |
Lower-intermediate | 40th–75th | 556 | 12 | 544 | 1:45 | 1 /46 | 0.48 |
Low-risk zone | <40th | 1756 | 0 | 1756 | 0 | 0 | 0 |
Total | 2840 | 126 | 2714 | 1:22 | 1 /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.