Correlation of transcutaneous bilirubinometry (TcB) and total serum bilirubin (TsB) levels after phototherapy

Abstract

Aim: To investigate the correlation between transcutaneous bilirubinometry (TcB) and total serum bilirubin (TsB) in jaundiced infants before and after, but not during phototherapy. Methods: This study prospectively investigated the correlation between TcB and TsB in term and near term infants before and after phototherapy. Results: Overall 673 pairs of measurements (TcB and TsB) were performed on 371 infants of ≥35 weeks gestation and with birth weight above 2000 g. Of these 337 sets were from 200 infants who had not been treated with phototherapy (Group 1) and 336 measurements from 171 infants taken between 1 h and 5 d after phototherapy (Group 2). The correlation coefficient between TcB and TsB in the whole cohort was r = 0.72. The correlation was low during the first 8 h after phototherapy (r = 0.56), but thereafter the correlation returned to the range of 0.65-0.8. Using the Sobel test, no significant difference was found between the correlation coefficients at the different time periods, with the possible exception of the difference between 1 and 8 h and 9 and 16 h which was of borderline significance with a p value of 0.06. Conclusion: This study demonstrates good correlation between TcB and TsB by 8 h after phototherapy. This adds validity to community-based screening programs employing TcB measurements plotted on TsB nomograms. Such programs may contribute to prevention of tragic cases of bilirubin-induced neurologic damage.

Effect of Phototherapy on the Reliability of Transcutaneous Bilirubin Devices in Term and Near-Term Infants: A Systematic Review and Meta-Analysis

“…Four of the included studies [27,32,34,35] also provided data for infants in the postphototherapy phase (fig. 4).…”

“…We identified 14 studies [17,23,24,25,26,27,28,29,30,31,32,33,34,35] providing 2,082 paired measurements of TcB and TSB in 1,319 patients who fulfilled the inclusion criteria (fig. 1).…”

“…The baseline characteristics of the included studies are presented in table 1. Studies varied in terms of: whether the site(s) of measurement were shielded from phototherapy; the actual site of TcB measurement (forehead = 12 studies; sternum = 5 studies and other sites = 2 studies); the TcB device used (Bilicheck = 1 study; JM 103 = 3 studies; JM 101 = 10 studies); the method used for serum bilirubin measurement (direct spectrophotometry only = 7 studies; diazo method only = 5 studies; both = 1 study, and method not specified = 1 study), and agreement statistic used for comparison (correlation coefficient = 14 studies [17,23,24,25,26,27,28,29,30,31,32,33,34,35], Bland-Altman difference plots = 2 studies [17,23]; 2 studies reported results with both methods). Four studies [27,32,34,35] provided data for the postphototherapy phase, as correlation coefficients.…”

“…In the study by Rylance et al [23], although the blood for estimation of TSB was collected at the time of TcB estimation, samples were processed once a day resulting in greater time lag and thus risk of degradation of bilirubin from light and heat [36]. Nine studies [17,23,25,26,29,30,32,33,35] conducted the TcB and TSB estimations simultaneously or within 30 min, whereas the remaining 5 [24,27,28,31,34] did not specify the time difference between the two tests.…”

Accuracy of transcutaneous bilirubin measurement in newborns after phototherapy

“…Forehead and sternum are the most commonly reported measurement sites, [11][12][13][14] performance of the bilirubinometer in other body sites after phototherapy has not been evaluated. The aim of this prospective study was to provide the missing data on the accuracy of the device in term Caucasian newborn infants who underwent phototherapy, considering four different measurement sites (exposed and unexposed) and two different modalities of phototherapy.…”