Functional organization of the central nervous system with respect to orientation in time.

Abstract

<b>Aims:</b> To compare the predictive performance of clinical risk factor assessment and pre-discharge bilirubin measurement as screening tools for identifying infants at risk of developing significant neonatal hyperbilirubinaemia (post-discharge total serum bilirubin (TSB) &gt;95th centile). <b>Methods:</b> Retrospective cohort study of term and near term infants born in an urban community teaching hospital in Pennsylvania (1993–97). A clinical risk factor scoring system was developed and its predictive performance compared to a pre-discharge TSB expressed as a risk zone on a bilirubin nomogram. Main outcome measures were prediction model discrimination, range of predicted probabilities, and sensitivity, specificity, positive and negative predictive values, and likelihood ratios for various positivity criteria. <b>Results:</b> The clinical risk factor scoring system developed included birth weight, gestational age &lt;38 weeks, oxytocin use during delivery, vacuum extraction, breast feeding, and combination breast and bottle feeding. The pre-discharge bilirubin risk zone had better discrimination (c = 0.83; 95% CI 0.80 to 0.86) than the clinical risk factor score (c = 0.71; 95% CI 0.66 to 0.76) and predicted risk of significant hyperbilirubinaemia as high as 59% compared with a maximum of 44% for the clinical risk factor score. Neither the risk score nor the pre-discharge TSB risk zone predicted the outcome with ⩾0.98 sensitivity without significantly compromising specificity (0.13 and 0.21, respectively). Multi-level clinical risk factor scores and TSB risk zones produced likelihood ratios of 0.15–3.25 and 0.05–9.43, respectively. <b>Conclusions:</b> The pre-discharge bilirubin expressed as a risk zone on an hour specific bilirubin nomogram is more accurate and generates wider risk stratification than a clinical risk factor score.