False-negative results of pre-discharge neonatal bilirubin screening to predict severe hyperbilirubinemia: a need for caution

Transcutaneous bilirubin nomogram for the first 144 hours in Thai neonates

Objectives: To develop an hour-specific transcutaneous bilirubin (TcB) nomogram for Thai neonates and to compare the ability of this nomogram with that of Bhutani's total serum bilirubin (TSB) nomogram for prediction of significant hyperbilirubinemia requiring phototherapy.Methods: Healthy Thai neonates, gestational age ≥35-week-gestation and birth weight ≥2000 grams were enrolled. Neonates who could not attend the postdischarge follow-up at our center were excluded. TcB measurements were routinely performed at 6 am and 6 pm using JM103 transcutaneous bilirubinometer until the neonates were discharged or received phototherapy. TcB levels were also measured at least once during 24-72 hours after discharge and thereafter depending on the pediatricians' decision. The nomogram was developed from the TcB data during age 12-144 hours of neonates who did not require phototherapy. The TcB values that obtained predischarge or before receiving phototherapy of all neonates were used to determine the predictive ability of this nomogram and Bhutani's TSB nomogram.Results: A total of 1071 neonates were included. Two hundred forty-one neonates (22.5%) required phototherapy. The nomogram was constructed using 4834 hour-specific TcB values. It provided a good prediction with the area under curve (AUC) of 0.89. The 75th percentile tract revealed sensitivity and negative predictive value (NPV) of 87.1 and 95.4% while that of the 40th percentile tract were 97.9 and 98.5% respectively. When Bhutani's nomogram was used, the AUC was 0.84. The sensitivity and NPV of the 75th percentile tract were 56.4 and 88.2%, and for the 40th percentile tract were 97.1 and 98.0% respectively.Conclusion: The newly developed TcB nomogram revealed slightly better predictive ability than Bhutani's TSB nomogram for term and late preterm Thai neonates who were the population with high prevalence of significant hyperbilirubinemia. The 40th percentile curve of both nomograms should be considered as an appropriate cut-off level for prediction.

Transcutaneous bilirubinometry

Although the modern era of transcutaneous bilirubin monitoring (TcB) began only about 35 years ago, this screening tool is now widely used in newborn nurseries and outpatient clinics, offices, and emergency departments to obtain a rapid and non-invasive estimate of the degree of hyperbilirubinemia. TcB devices have become more sophisticated, and major breakthroughs include the following: (a) ability to report a bilirubin value rather than an index value, (b) enhanced correction for chromophores other than bilirubin, and (c) technologic improvements including interface with electronic medical records. Good agreement with laboratory bilirubin measurement has been demonstrated, and the ability of TcB screening to predict and decrease the incidence of subsequent hyperbilirubinemia has been well-documented. To date, it has not been shown that this screening results in improved long-term outcomes.

Plotting transcutaneous bilirubin measurements on specific transcutaneous nomogram results in better prediction of significant hyperbilirubinemia in healthy term and near-term newborns: a pilot study

BACKGROUND

The American Academy of Pediatrics has recommended a systematic assessment before discharge for the risk of severe hyperbilirubinemia. Plotting total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) on a TSB hour-specific nomogram is proposed as a tool for laboratory evaluation.

OBJECTIVES

The aim of this study was to compare the predictive characteristics, particularly the incidence of false negative rate (FNR), of the practice of plotting TcB values on the TSB hour-specific risk nomogram versus on transcutaneous nomogram.

METHODS

Paired TSB and TcB measurements were conducted on 141 newborns. Risk of developing significant hyperbilirubinemia was defined as infants with bilirubin level ≥ 75% on TSB or ≥ 95% on TcB nomogram. TSB values, plotted on the TSB nomogram of Bhutani et al. [Pediatrics 1999;103:6-14], were used as reference. TcB values were plotted on the TSB nomogram and on the transcutaneous nomograms of Maisels and Kring [Pediatrics 2006;117:1169-1173] and Fouzas et al. [Pediatrics 2010;125:e52-e57].

RESULTS

Plotting TcB measurements on a TSB nomogram resulted in a trend towards a higher FNR when compared to Maisels' and Fouzas' nomograms (18.0/1,000 compared to 10.2/1,000 and 8.6/1,000 respectively). Although not statistically significant, plotting TcB on transcutaneous nomogram resulted in better predictive values with the Fouzas' nomogram, having the best sensitivity (90.0%) and specificity (87.79%) as well as the highest positive (35.97%) and negative (99.14%) predictive value.

CONCLUSION

Plotting TcB on a TSB nomogram may result in increased rate of FNR and decreased predictive characteristics. The practice of plotting TcB on a TSB nomogram needs further evaluation.

BiliCheck vs JM-103 in identifying neonates not at risk of hyperbilirubinaemia

Background

Transcutaneous bilirubinometry is widely used to predict hyperbilirubinemia by using several devices. The aim of this study was to compare the predictive ability of BiliCheck vs JM-103 in identifying neonates not at risk of significant hyperbilirubinemia, putting the data obtained with the two instruments on our transcutaneous bilirubin nomogram built with the BiliCheck.

Methods

Transcutaneous bilirubin (TcB) measurement was performed when jaundice appeared in newborn babies and/or just before discharge from the hospital. It was performed at the forehead with the two instruments within 5 minutes by two experienced neonatologists, each one blind to the value obtained by the other. Blood samples were drawn to obtain total serum bilirubin (TSB) levels soon after TcB measurements.

Results

A total of 627 paired-sample measurements were obtained from 298 newborn babies. Out of the total population studied, 16 newborn babies (5.4%) showed significant hyperbilirubinemia defined as TSB value >17 mg/dL, or as need for phototherapy treatment according to the AAP guidelines. TcB measurements showed false negative results in the first 60 hours of life using both devices. After the 60^th hour of life, TcB measurements using both devices successfully predicted newborn babies not at risk of significant hyperbilirubinemia, being the JM-103 more reliable than BC because of fewer false positive results.

Conclusions

Our study shows that both BC and JM-103 can exclude subsequent significant hyperbilirubinemia when the measurements are performed after the 60^th hour of life. Nevertheless, the transcutaneous pre-discharge screening should be considered only as the first step, and it has to be followed by a follow-up through the first days after discharge.

Trends of transcutaneous bilirubin in neonates who develop significant hyperbilirubinemia

OBJECTIVES

To provide data on the natural course of transcutaneous bilirubin (TcB) levels in neonates before the development of significant hyperbilirubinemia, and to assess the effect of different demographic and perinatal factors on the rate of TcB increase.

METHODS

We analyzed 2454 TcB measurements from 419 neonates before the development of significant hyperbilirubinemia. Mean TcB values and TcB percentiles for designated times were calculated, and the effect of different risk factors on the rate of TcB increase was assessed. TcB percentile curves were plotted for comparison on a population-based TcB nomogram.

RESULTS

Blood incompatibilities and glucose-6-phosphate dehy-drogenase deficiency were associated with higher rates of TcB in-crease during the first 36 to 48 postnatal hours, whereas smaller gestational age, increased weight loss, and exclusive breastfeeding had a similar but later effect. Compared with general population norms, a different pattern of TcB increase was noted in neonates who developed significant hyperbilirubinemia, but with a sub-stantial overlap of TcB values during the first 24 to 48 postnatal hours.

CONCLUSIONS

We provide data on the natural course of TcB levels before the development of significant hyperbilirubinemia in a white population of term and near-term neonates. Smaller gestational age, blood incompatibilities, glucose-6-phosphate dehydrogenase deficiency, increased weight loss, and exclusive breastfeeding significantly affected the rate of TcB increase in a time-dependent manner. These findings may assist in assessing the risk for significant hyperbilirubinemia and planning appropriate follow-up strategies for neonates with borderline bilirubin levels.

Neonatal hyperbilirubinemia in the low-intermediate-risk category on the bilirubin nomogram

OBJECTIVE

Predischarge bilirubin screening predicts neonatal hyperbilirubinemia. We evaluated the incidence of false-negative bilirubin screening among readmissions for hyperbilirubinemia.

METHODS

In healthy term and late preterm, predominantly breastfeeding newborns, predischarge transcutaneous bilirubin values were plotted on the hour of life-specific bilirubin nomogram and confirmed with plasma total bilirubin in those with a transcutaneous reading ≥ 75th percentile, or between the 41st and 75th percentiles in the presence of predictive icterogenic risk factors. False-negative bilirubin screen was defined as a predischarge bilirubin value ≤ 75th percentile in a newborn who was subsequently readmitted for phototherapy.

RESULTS

Of a total of 25439 neonates born between 2008 and 2009, 143 (0.56%) were readmitted with a mean plasma total bilirubin of 18.7 ± 1.7 mg/dL at 125 ± 54 hours. False-negative predischarge bilirubin screen was identified in 46 (32.2%). Of these, 6 (4.2%) were in the low-risk zone (≤ 40th percentile, relative risk [RR] = 1) and 40 (28%) in the intermediate-low-risk zone (41st-75th percentile, RR 7.62 [95% confidence interval 3.23-17.96]). Of those in the high-risk zones, 76 (53.1%) were in the intermediate-high-risk zone (76th-95th percentile, RR 25.32 [11.03-58.10]) and 21 (14.7%) in the high-risk zone (>95th percentile, RR 27.78 [11.23-68.70]).

CONCLUSIONS

Predischarge bilirubin levels in newborns classified as low risk did not eliminate the risk of readmission for hyperbilirubinemia. All newborns including those at low risk must be vigilantly observed for subsequent hyperbilirubinemia.

Development and validation of serum bilirubin nomogram to predict the absence of risk for severe hyperbilirubinaemia before discharge: a prospective, multicenter study

Background

Early discharge of healthy late preterm and full term newborn infants has become common practice because of the current social and economic necessities. Severe jaundice, and even kernicterus, has developed in some term infants discharged early. This study was designed to elaborate a percentile-based hour specific total serum bilirubin (TSB) nomogram and to assess its ability to predict the absence of risk for subsequent non physiologic severe hyperbilirubinaemia before discharge.

Methods

A percentile-based hour-specific nomogram for TSB values was performed using TSB data of 1708 healthy full term neonates. The nomogram's predictive ability was then prospectively assessed in five different first level neonatal units, using a single TSB value determined before discharge.

Results

The 75 ^th percentile of hour specific TSB nomogram allows to predict newborn babies without significant hyperbilirubinemia only after the first 72 hours of life. In the first 48 hours of life the observation of false negative results did not permit a safe discharge from the hospital.

Conclusion

The hour-specific TSB nomogram is able to predict all neonates without risk of non physiologic hyperbilirubinemia only after 48 to 72 hours of life. The combination of TSB determination and risk factors for hyperbilirubinemia could facilitate a safe discharge from the hospital and a targeted intervention and follow-up.

Cost-effectiveness analysis of a system-based approach for managing neonatal jaundice and preventing kernicterus in Ontario

OBJECTIVE

To evaluate the incremental cost-effectiveness of a system-based approach for the management of neonatal jaundice and the prevention of kernicterus in term and late-preterm (≥35 weeks) infants, compared with the traditional practice based on visual inspection and selected bilirubin testing.

STUDY DESIGN

Two hypothetical cohorts of 150,000 term and late-preterm neonates were used to compare the costs and outcomes associated with the use of a system-based or traditional practice approach. Data for the evaluation were obtained from the case costing centre at a large teaching hospital in Ontario, supplemented by data from the literature.

RESULTS

The per child cost for the system-based approach cohort was $176, compared with $173 in the traditional practice cohort. The higher cost associated with the system-based cohort reflects increased costs for predischarge screening and treatment and increased postdischarge follow-up visits. These costs are partially offset by reduced costs from fewer emergency room visits, hospital readmissions and kernicterus cases. Compared with the traditional approach, the cost to prevent one kernicterus case using the system-based approach was $570,496, the cost per life year gained was $26,279, and the cost per quality-adjusted life year gained was $65,698.

CONCLUSION

The cost to prevent one kernicterus case using the system-based approach is much lower than previously reported in the literature.

Validation of transcutaneous bilirubin nomogram in identifying neonates not at risk of hyperbilirubinaemia: a prospective, observational, multicenter study

BACKGROUND

Transcutaneous bilirubin (TcB) measurement is widely used as screening for neonatal hyperbilirubinaemia.

AIMS

To prospectively validate TcB measurement using hour-specific nomogram in identifying newborn infants not at risk for severe hyperbilirubinaemia.

STUDY DESIGN

prospective, observational, multicenter.

SUBJECTS

2167 term and late preterm infants born in 5 neonatal units in the Lazio region of Italy.

METHODS

All neonates had simultaneous TcB and total serum bilirubin (TSB) measurements, when jaundice appeared and/or before hospital discharge. TcB and TSB values were plotted on a percentile-based hour-specific transcutaneous nomogram previously developed, to identify the safe percentile able to predict subsequent significant hyperbilirubinaemia defined as serum bilirubin >17 mg/dL or need for phototherapy.

RESULTS

Fifty-five babies (2.5%) developed significant hyperbilirubinaemia. The 50th percentile of our nomogram was able to identify all babies who were at risk of significant hyperbilirubinaemia, but with a high false positive rate. Using the 75th percentile, two false negatives reduced sensitivity in the first 48 hours but we were able to detect all babies at risk after the 48th hour of age.

CONCLUSIONS

This study demonstrates that the 75th percentile of our TcB nomogram is able to exclude any subsequent severe hyperbilirubinaemia from 48 h of life ahead.

Clinical and genetic risk factors for moderate hyperbilirubinemia in Brazilian newborn infants

OBJECTIVE

To identify clinical and genetic risk factors for moderate hyperbilirubinemia during the first week of life.

STUDY DESIGN

Using univariate and multivariate multiple regression analyses, the RR for clinical factors, the African variant of glucose-6-phosphate dehydrogenase (G6PD) deficiency (G202A/A376G), and (TA)(n) UGT1A1 polymorphisms were established in a cohort of 608 Brazilian newborn infants. Hyperbilirubinemia was monitored until 134.5 ± 49.8 h of life (IQR, 111.0 to 156.7). The dependent variable was total bilirubinemia (TB) ≥12.9 mg per 100 ml estimated by transcutaneous or plasma bilirubin measurements.

RESULT

The African variant of G6PD deficiency and (TA)(7)/(TA)(7) and (TA)(7)/(TA)(8) polymorphisms present in 6.1 and 12.0% of newborns, respectively, were not risk factors for moderate hyperbilirubinemia. Coexpression of G6DP deficiency and UGT1A1 polymorphisms occurred in 0.49% of the subjects. Independent clinical predictors for TB≥ 12.9 mg per 100 ml were gestational age <38 weeks and reference curve percentiles >P40th.

CONCLUSION

In this study, G6PD deficiency and UGT1A1 gene promoter polymorphisms were not risk factors for moderate hyperbilirubinemia. Genetic factors may vary considerably in importance among different populations.

Assessing jaundice in infants of 35-week gestation and greater

PURPOSE OF REVIEW

In 2004, the American Academy of Pediatrics officially recommended universal predischarge risk assessment for severe neonatal hyperbilirubinemia with the goal of minimizing subsequent risk of chronic bilirubin encephalopathy (formerly known as kernicterus). In this article, we review recent research regarding jaundice predischarge risk assessment, current expert recommendations for universal predischarge bilirubin screening, and concerns expressed in the literature regarding these recommendations.

RECENT FINDINGS

A group of experts have recently recommended universal predischarge bilirubin screening to identify newborns at risk for developing severe neonatal hyperbilirubinemia. In contrast, the United States Preventive Services Task Force states that there is insufficient evidence to make this recommendation. Transcutaneous bilirubinometry has emerged as a noninvasive, quick method to screen for neonatal hyperbilirubinemia, although refinement and validation of transcutaneous bilirubin nomograms are needed. Newer studies suggest that the combined use of a predischarge bilirubin and gestational age risk assessment offers a simple, objective, and accurate way to identify infants at risk for subsequent, severe hyperbilirubinemia.

SUMMARY

All newborns should be systematically assessed for risk of developing severe hyperbilirubinemia prior to hospital discharge. Although limited data exist to recommend its use universally, predischarge bilirubin screening should be considered given recent expert opinion. The role of transcutaneous bilirubinometry remains promising, although further research evaluating and validating its use in varied and diverse populations is imperative. Combined models of risk assessment may offer the best approach to identifying infants at risk for subsequent, severe hyperbilirubinemia.