Sixth-Hour Trancutaneous Bilirubin and Need for Phototherapy in DAT Positive Newborns

Abstract

OBJECTIVES To characterize the outcomes of ABO incompatible direct antiglobulin test (DAT) positive newborns and determine the predictive ability of a sixth-hour transcutaneous bilirubin (TcB for needing phototherapy ≤24 hours of age. METHODS Retrospective, cross-sectional study from May 2013 to March 2017. Of 10 942 consecutive newborns ≥35 weeks estimated gestational age, 829 were ABO incompatible and DAT positive. After excluding for antibodies other than ABO (51), missing data (4), miscategorization of blood type O (1), and duplicate record (1), 772 newborns remained. Of 772, a subsample of 346 newborns with both TcB and total serum bilirubin (TSB) tests within 1 hour of the sixth hour was analyzed to determine the predictive ability. RESULTS Phototherapy was required in 281 of 772 (36.4%); 156 (20.2%) in the first 24 hours. There were 10 (1.3%) admissions for hyperbilirubinemia to the NICU for intravenous immunoglobin. Birth weight, infant blood type B, TSB, reticulocyte count, and TcB were all significantly associated with phototherapy ≤24 hours. On multivariate analysis, significant predictors of phototherapy ≤24 hours were TSB and reticulocyte count if no TcB was done and TcB alone if no blood tests were done. TcB was highly predictive (odds ratio 3.1, 95% confidence interval: 2.4–4.0) and nearly as accurate as the TSB and reticulocyte count (area under the curve, 0.90 and 0.96, respectively). Low (<3.0 mg/dL) and high (≥5.3 mg/dL) risk TcB cutoffs demonstrated a negative predictive value of 98% and positive predictive value of 85%, respectively. CONCLUSIONS Among high-risk ABO incompatible DAT positive newborns, the sixth-hour TcB is highly predictive of the need for phototherapy ≤24 hours.

Early Transcutaneous Bilirubin Levels in Term High-Risk Newborn Infants

“…Using the TcB values from the studies by Papacostas et al 4 and Varvarigou et al, 5 we calculated the incremental difference in TcB (Table 1). These studies were selected as we looked at the first 6 hours of bilirubin level.…”

“… Abbreviation: TcB, transcutaneous bilirubin. a Predicted from mean TcB value over 6 hours (0.7/6 = 0.11 per hour)—Supplementary Figure. b Obtained from TcB high-risk Table 3 of Papacostas et al 4 c Obtained from TcB high-risk nomogram, Figure 3, of Varvarigou et al 5 …”

“…2 However, the established TcB nomograms do not have TcB values starting at birth. [3][4][5] There is a gap and a need to develop a TcB nomogram that has TcB values starting at birth. The ideal way to develop such a TcB nomogram is to obtain serial hourly TcB levels in several newborn infants, which requires serial measurements interuppting nursery care.…”