Transcutaneous versus Total Serum Bilirubin Measurements in Preterm Infants

Hyperbilirubinemia screening and treatment in neonates born prior to 35 weeks of gestation

BACKGROUND

Guidelines on when to screen for neonatal hyperbilirubinemia apply to infants born at 35 weeks or later of gestation. It is unknown whether infants born earlier would benefit from similar guidelines. Our objective was to examine hyperbilirubinemia screening and phototherapy prescription among early preterm infants during the first 6 days of life.

METHODS

We reviewed the charts of 193 infants born prior to 35 weeks of gestation who were admitted to a tertiary care NICU in Southeastern Ontario in 2018-2019. Information on total serum bilirubin (TSB) measurements over each 12-hour interval during the first six days of life and the treatment decision (no treatment, initiate, continue, or stop phototherapy) was extracted. We also examined what proportion of infants were prescribed phototherapy during each 12-hour interval.

RESULTS

Of 1006 TSB measurements performed over the first 6 days of life, 605 were done to determine whether phototherapy should be initiated. Treatment was prescribed in 275 instances (45%). A higher proportion of infants born prior to 28 weeks of gestation required phototherapy in the first 12 hours of life (37%) compared to those born at 28-32 weeks (20%) and 33-34 weeks (5.7%).

CONCLUSIONS

Our results suggest that TSB measurements are often poorly timed to detect treatment need in infants born prior to 35 weeks of gestation. This unnecessarily increases the risk of complications from phlebotomy and is an ineffective use of health care resources. There is a need to develop guidelines to optimize hyperbilirubinemia screening among early preterm infants.

Transcutaneous Bilirubin Accuracy Before, During, and After Phototherapy: A Meta-Analysis

CONTEXT

Transcutaneous bilirubinometry (TcB) is used as a valid screening to identify neonates requiring measurement of total serum bilirubin (TSB) before phototherapy. Its use during and after phototherapy is not advised yet because of unknown reliability.

OBJECTIVES

To determine the agreement of TcB and TSB measurements before, during, and after phototherapy.

DATA SOURCES

PubMed Medline, Cochrane Library, and references of eligible studies were searched.

STUDY SELECTION

Prospective and retrospective cohort and cross-sectional studies reporting Bland-Altman statistics of paired TcB and TSB measurements in term and preterm newborns.

DATA EXTRACTION

Meta-analysis was performed using the Mantel-Haenszel weighted approach. The agreement between TcB and TSB in μmol/L was described by pooled mean differences (MDs) and limits of agreement (LoA).

RESULTS

Fifty-four studies were included. The pooled MD before phototherapy is 2.5 μmol/L (LoA -38.3 to 43.3). The pooled MD during phototherapy is -0.3 μmol/L (LoA -34.8 to 34.2) on covered skin and -28.6 μmol/L (LoA -105.7 to 48.5) on uncovered skin. The pooled MD after phototherapy is -34.3 μmol/L (LoA -86.7 to 18.1) on covered skin and -21.1 μmol/L (LoA -88.6 to 46.4) on uncovered skin. Subgroup analysis revealed the best agreement at the forehead. We did not find any difference in agreement between term and preterm neonates.

LIMITATIONS

Language restriction.

CONCLUSIONS

TcB measurements before and during phototherapy on covered skin show good agreement compared with TSB in term and preterm newborns. More studies are needed to evaluate the accuracy after phototherapy.

The Accuracy of Transcutaneous Bilirubin as a Screening Test in Preterm Infants

OBJECTIVE

To determine the accuracy of transcutaneous bilirubin (TcB) to predict total serum bilirubin (TSB) in preterm infants across gestational age (GA) ranges and to calculate the cost-effectiveness of TcB as the primary screening test of choice for neonatal jaundice in neonatal intensive care unit (NICU) settings.

METHODS

Single-center retrospective study of infants aged ≤ seven days admitted to the NICU over a six-month period with a paired TSB and TcB, with or without phototherapy as part of their routine clinical care. Infants were divided into GA-specific groups as term, late preterm, moderate preterm, and very preterm. Measurement bias (bias=TSB-TcB) was calculated on the paired TSB and TcB values, and a Bland-Altman analysis was carried out. The impacts of additional infant-specific variables on the bias were assessed with univariate and multivariate linear regression techniques. The potential direct cost savings associated with the use of TcB as the primary screening test were calculated.

RESULTS

A total of 263 paired TSB and TcB samples from 95 patients were included (130 paired samples from term (n=60), 75 from late preterm (n=21), 27 from moderate preterm (n=7), and 31 from very preterm (n=7)). The mean paired measurement bias across all the GA groups was -0.9 ± 2.9 mg/dL. The sensitivity and specificity of TcB in GA < 35 weeks were 92% and 62%, respectively. A conservative estimate of a one-third reduction in TSB measurement by using TcB as the primary screening test will have a direct cost saving of $3,148 over a six-month period.

CONCLUSION

Our data suggest that TcB is a safe and potentially cost-effective screening test for jaundice across GA groups.

Transcutaneous bilirubinometry versus total serum bilirubin measurement for newborns

BACKGROUND

Jaundice is a very common condition in newborns, affecting up to 60% of term newborns and 80% of preterm newborns in the first week of life. Jaundice is caused by increased bilirubin in the blood from the breakdown of red blood cells. The gold standard for measuring bilirubin levels is obtaining a blood sample and processing it in a laboratory. However, noninvasive transcutaneous bilirubin (TcB) measurement devices are widely available and used in many settings to estimate total serum bilirubin (TSB) levels.

OBJECTIVES

To determine the diagnostic accuracy of transcutaneous bilirubin measurement for detecting hyperbilirubinaemia in newborns.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL and trial registries up to 18 August 2022. We also checked the reference lists of all included studies and relevant systematic reviews for other potentially eligible studies.

SELECTION CRITERIA

We included cross-sectional and prospective cohort studies that evaluated the accuracy of any TcB device compared to TSB measurement in term or preterm newborn infants (0 to 28 days postnatal age). All included studies provided sufficient data and information to create a 2 × 2 table for the calculation of measures of diagnostic accuracy, including sensitivities and specificities. We excluded studies that only reported correlation coefficients.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the eligibility criteria to all citations from the search and extracted data from the included studies using a standard data extraction form. We summarised the available results narratively and, where possible, we combined study data in a meta-analysis.

MAIN RESULTS

We included 23 studies, involving 5058 participants. All studies had low risk of bias as measured by the QUADAS 2 tool. The studies were conducted in different countries and settings, included newborns of different gestational and postnatal ages, compared various TcB devices (including the JM 101, JM 102, JM 103, BiliChek, Bilitest and JH20-1C) and used different cutoff values for a positive result. In most studies, the TcB measurement was taken from the forehead, sternum, or both. The sensitivity of various TcB cutoff values to detect significant hyperbilirubinaemia ranged from 74% to 100%, and specificity ranged from 18% to 89%.

AUTHORS' CONCLUSIONS

The high sensitivity of TcB to detect hyperbilirubinaemia suggests that TcB devices are reliable screening tests for ruling out hyperbilirubinaemia in newborn infants. Positive test results would require confirmation through serum bilirubin measurement.

Feasibility analysis of TCB, hs-CRP, and UCB/ALB as outcome measures for dynamic assessment during phototherapy of neonates with Hyperbilirubinemia

Hyperbilirubinemia (HY) is a common condition in neonates that requires phototherapy treatment. This study aimed to evaluate the effectiveness of transcutaneous bilirubin measurements (TCB), hypersensitive C-reactive protein (hs-CRP), and unconjugated bilirubin (UCB)/albumin (ALB) as indicators of HY during neonatal phototherapy. A research group of 67 neonates with pathological HY and a control group of 55 healthy neonates were selected from a hospital between June 2020 and May 2021. TCB, hs-CRP, and UCB/ALB tests were performed before, during (at 3 days of treatment), and after (at 6 days of treatment) phototherapy in the research group and at admission in the control group. The study also included a 1-year prognostic follow-up on the research group. The study observed the difference in TCB, hs-CRP, and UCB/ALB test results between both groups and their assessment effect on adverse reactions, treatment effects, and poor prognosis in phototherapy. TCB, hs-CRP, and UCB/ALB levels were higher in the research group than in the control group and gradually decreased during phototherapy (P < 0.05). The combined TCB, hs-CRP, and UCB/ALB assay had 100.0% sensitivity and 64.58% specificity (P < 0.001) for predicting adverse reactions, 88.24% sensitivity and 80.00% specificity (P < 0.001) for predicting the effect of phototherapy, and 90.91% sensitivity and 88.89% specificity (P < 0.001) for predicting poor prognosis. The combined TCB, hs-CRP, and UCB/ALB assay showed superior assessment of adverse effects, clinical outcomes, and poor prognosis in HY neonates treated with phototherapy. TCB, hs-CRP, and UCB/ALB could be used as dynamic disease assessment indicators for HY to better prevent and treat the occurrence of HY.

Bilirubin Encephalopathy

PURPOSE OF REVIEW

Hyperbilirubinemia is commonly seen in neonates. Though hyperbilirubinemia is typically asymptomatic, severe elevation of bilirubin levels can lead to acute bilirubin encephalopathy and progress to kernicterus spectrum disorder, a chronic condition characterized by hearing loss, extrapyramidal dysfunction, ophthalmoplegia, and enamel hypoplasia. Epidemiological data show that the implementation of universal pre-discharge bilirubin screening programs has reduced the rates of hyperbilirubinemia-associated complications. However, acute bilirubin encephalopathy and kernicterus spectrum disorder are still particularly common in low- and middle-income countries.

RECENT FINDINGS

The understanding of the genetic and biochemical processes that increase the susceptibility of defined anatomical areas of the central nervous system to the deleterious effects of bilirubin may facilitate the development of effective treatments for acute bilirubin encephalopathy and kernicterus spectrum disorder. Scoring systems are available for the diagnosis and severity grading of these conditions. The treatment of hyperbilirubinemia in newborns relies on the use of phototherapy and exchange transfusion. However, novel therapeutic options including deep brain stimulation, brain-computer interface, and stem cell transplantation may alleviate the heavy disease burden associated with kernicterus spectrum disorder. Despite improved screening and treatment options, the prevalence of acute bilirubin encephalopathy and kernicterus spectrum disorder remains elevated in low- and middle-income countries. The continued presence and associated long-term disability of these conditions warrant further research to improve their prevention and management.

The Impact of Phototherapy on the Accuracy of Transcutaneous Bilirubin Measurements in Neonates: Optimal Measurement Site and Timing

Transcutaneous bilirubinometer devices are widely applied to assess neonatal hyperbilirubinemia. However, the optimal skin site and timing of transcutaneous bilirubin (TCB) measurements for the strongest correlation with total serum bilirubin (TSB) levels after phototherapy are still unclear. We conducted a retrospective observational study evaluating the correlation of TCB and TSB levels in neonates postphototherapy. The TCB measurements on the forehead and mid-sternum at 0 and 30 min postphototherapy were assessed by using a JM-103 bilirubinometer. Paired TCB and TSB measurements were assessed by Pearson correlation and Bland–Altman plots. We analyzed 40 neonates with 96 TSB and 384 TCB measurements. The TSB level correlated moderately with the forehead TCB level at 30 min postphototherapy (r = 0.65) and less strongly with the midsternum TCB level at 0 min postphototherapy (r = 0.52). The forehead at 30 min after cessation of phototherapy was the best time point and location of TCB measurement for the assessment of neonatal jaundice status. The reliability of TCB measurements varied across skin sites and durations after phototherapy. The effectiveness of TCB measurement to assess neonatal hyperbilirubinemia is much better on covered skin areas (foreheads) 30 min postphototherapy. The appropriate application of transcutaneous bilirubinometers could aid in clinical practice and avoid unnecessary management.