Prediction of hyperbilirubinaemia in the healthy term newborn

The aim is to establish the correlation between transcutaneous bilirubin (TCB) and serum bilirubin (TSB) and its predictive value for significant hyperbilirubinaemia greater than or equal to 290 mcmol/L (17 mg/dL). We studied a total of 2004 healthy full-term newborns, weight 3.230 g +/- 491 g; 90% received breast milk. The study was performed in two phases. In the first phase (610 newborns), the following tests were carried out: hematocrit and bilirubin in umbilical cord blood; TCB at 24 h, 48 h and between 60 h and 96 h at the forehead and over the sternum: TSB was measured along with this last test. In the second phase (1394 newborns), the predictive value of TCB and TSB was validated. The incidence of bilirubin greater than or equal to 290 mcmol/L was 2.95% and 3.2%. The correlation between TSB and TCB is high (n = 996; r = 0.92; y = 5.916 + 0.804x; p < 0.000). There was a better correlation between TCB and TSB with sternal compared to forehead determination (<24 h: 0.81 vs 0.77; 24-48 h: 0.887 vs 0.83; and >48 h: 0.94 vs 0.83). The study showed the scant sensitivity of umbilical cord blood bilirubin and good predictive value at 24 h of TSB greater than or equal to 102 mcmol/L (6 mg/dL) and at 48 h of TSB greater than or equal to 154 mcmol/L (9 mg/dL) and TCB greater than or equal to 13 (equivalent to 154 mcmol/L). Conclusion: There is a good correlation between TCB and TSB. In infants with TSB greater than or equal to 102 mcmol/L at 24 h or TSB greater than or equal to 154 mcmol/L or transcutaneous readings greater than or equal to 13 h at 48 h, a TSB test must be performed after 48 h of life.