Evaluation of a new transcutaneous bilirubinometer in newborn infants

Abstract

To avoid brain damage in newborn infants, effective tools for prevention of excessive neonatal hyperbilirubinemia are needed. The objective of this study was to evaluate a new transcutaneous bilirubinometer (JAISY). For this purpose, 930 bilirubin measurements were performed in 141 newborn infants born near-term or at term (gestational age 35-41 weeks; postnatal age 1-6 days; 71 boys; including 29 infants with darker skin) and compared to those of a previously validated instrument (JM105). In each infant, the mean of three repeated measurements in the forehead was calculated for each instrument, followed by a similar measurement on the chest. The bilirubin values varied between 0 and 320 µmol/l (0-18.8 mg/dl). There was a high degree of agreement with significant correlations between bilirubin values measured with the two devices on the forehead (Pearson's r = 0.94, p < 0.001) and the chest (r = 0.94, p < 0.001). The correlations remained after stratifying the data by gestational age, postnatal age and skin color. The coefficient of variation for repeated bilirubin measurements was 8.8% for JAISY and 8.0% for JM105 (p = 0.79). In conclusion, JAISY provides accurate and reproducible information on low to moderately high bilirubin levels in newborn infants born near-term or at term.

Figure 1

Photograph showing the two devices used in the study (JAISY to the left and JM105 to the right, measuring tape graded in centimeters).

Figure 2

Correlation between t.c. bilirubin values (μmol/L) measured with JM105 and JAISY in the chest (β = 0.92, r = 0.94, p < 0.001) and forehead (β = 0.97, r = 0.94, p < 0.001) of 141 newborn infants (gestational age 35–41 weeks, postnatal age 1–6 days). Filled circles in blue = tester 1 and unfilled circles = tester 2.

Figure 3

Bland–Altman plot with mean ± 2SD for an agreement between JM105 and JAISY measurements of t.c. bilirubin levels (μmol/L) in newborn infants. Unfilled circles = measurements at the chest, filled circles = measurements at the forehead. Mean = JM105 + JAISY/2. Difference = JM105 − JAISY.

Figure 4

Correlation coefficients for t.c. bilirubin values measured with JM105 and JAISY at the forehead and chest, by gestational age. Numbers in each bar indicate the number of infants.

Figure 5

Correlation coefficients for t.c. bilirubin values measured with JM105 and JAISY in the forehead and chest, by postnatal age. Numbers in each bar indicate the number of infants.