Transcutaneous bilirubin measurement: evaluation of Bilitest

Abstract

Objective: The early discharge of neonates from hospitals makes transcutaneous measurement of total serum bilirubin concentration a useful tool to monitor neonatal jaundice. The objective of this study was to evaluate the Bilitest BB 77trade mark (Bertocchi SRL Elettromedicali, Cremona, Italy), a new device for noninvasive transcutaneous total bilirubin measurement.

Methods: We studied 241 newborn infants > or =32 weeks of gestation admitted to the Neonatal Nursery of Careggi University Hospital, Florence. These infants had total serum bilirubin (TSB) levels measured by a standard laboratory test [corrected] as part of their normal care, and transcutaneous bilirubin (TcB) levels were obtained within 10 min after heel pricking.

Results: There was a good correlation between TSB and TcB values. The linear regression plot showed a general underestimation of Bilitest BB 77 measurement compared to standard laboratory test; the negative difference between Bilitest BB 77 values and TSB increased at higher bilirubin levels, as confirmed by the Bland-Altman error plot. To visualize the accuracy of the Bilitest BB 77 measurements, ROC curves plot sensitivity versus specificity and the maximum range of difference between Bilitest BB 77 and TSB were considered. Pearson correlation analysis demonstrated that Bilitest BB 77 accuracy was independent of gestational and postnatal age of newborns.

Conclusion: We conclude that the Bilitest BB 77, a new device for bilirubin transcutaneous measurement, shows a good correlation with standard laboratory method and has the merit to be quite inexpensive and does not need calibration with consumable or disposable parts. However, because TcB measurements with Bilitest BB 77 underestimated STB levels particularly at STB > or =12 mg/dl, serum bilirubin measurements are still required when treatment with phototherapy or exchange transfusion is being considered.