Comparison of measurements of transcutaneous and capillary blood bilirubin levels with the serum bilirubin levels being the reference method in the neonatal period

Objective: Total serum bilirubin (TSB) measurement in the laboratory, which is the standard method for monitoring newborns with jaundice but is invasive, stressful and time-consuming for newborns. It is reported that the measurements of transcutaneous bilirubin (TcB) that widely used in newborns with jaundice, especially in sick and premature newborns may be incorrect. It is expected that another method spectrophotometric capillary bilirubin (SCB) measurement may be more compatible with TSB measurements. In patients at different risk groups, we investigated the accuracy of the results TcB and SCB levels performed simultaneous measurements with TSB levels in newborns with jaundice. Materials and Methods: The study included 174 newborns who were hospitalized in the neonatal unit of Inönü University Turgut Özal Medical Center and who were examined for TSB levels for jaundice. Patients with direct hyperbilirubinemia, who were already receiving phototherapy, and patients who had skin diseases were excluded from study. The main clinical and demographic characteristics, prior phototherapy, blood group incompatibility of the patients were recorded. SCB and TcB (forehead, sternum and back) measurements were performed simultaneously with TSB. Results: The mean gestasionel age of the patients was 35.7±2.9 weeks and 10 (5.7%) of them had ABO or Rh incompatibility. The TSB level of 37 (21.3%) patients was ≥15 mg/dl. SCB and TcB levels were correlated with TSB levels in all patients and in the subgroup with a birth week ≤34 weeks. The highest correlation coefficient in TcB measurements was found in sternum measurements. The SCB, TcB back and sternum measurements were significantly correlated with TSB measurements in groups with birth weight ≤1500g (n=14) or TSB level ≥15 mg/dL. The correlation coefficient of SCB results was significantly highest in these groups. In patients who received phototherapy within the previous 12 hours, the TSB&SCB correlation was significant, while the TSB&TcB correlation was not significant. Conclusions: SCB measurement can be used in place of TCB or in combination with TCB, especially in sick newborns. SCB measurement should be preferred over TcB measurements in newborns who have recently received phototherapy. The accuracy of TcB measurements made from the sternum is highest. Key Words: Jaundice, newborn, spectrophotometric capillary bilirubin, transcutaneous bilirubin