Measurements of neonatal bilirubin and albumin concentrations: a need for improvement and quality control

A Significant Increase in the Incidence of Neonatal Hyperbilirubinemia and Phototherapy Treatment Due to a Routine Change in Laboratory Equipment

CONTEXT.—

Total serum bilirubin (TSB) analysis is pivotal for diagnosing neonatal hyperbilirubinemia. Because of a routine change in laboratory equipment, our TSB assay changed from a diazo to a vanadate oxidase method. Upon implementation, TSB results were substantially higher in newborns than expected based on the validation.

OBJECTIVE.—

To investigate the application of TSB and intermethod differences in neonates and their impact on phototherapy treatment.

DESIGN.—

The diazo and vanadate methods were compared directly using neonatal and adult samples. Anonymized external quality control data were analyzed to explore interlaboratory differences among 8 commercial TSB assays. Clinical patient data were extracted from the medical records to investigate the number of newborns receiving phototherapy.

RESULTS.—

The mean bias of the vanadate versus the diazo TSB method was +17.4% and +3.7% in neonatal and adult samples, respectively. External quality control data showed that the bias of commercial TSB methods compared with the reference method varied from -3.6% to +20.2%. Within-method variation ranged from 5.2% to 16.0%. After implementation of the vanadate TSB method, the number of neonates treated with phototherapy increased approximately threefold.

CONCLUSIONS.—

Currently available TSB assays lack harmonization for the diagnosis of neonatal hyperbilirubinemia. Between-methods differences are substantially higher in neonatal compared with adult samples, highlighting the importance of including neonatal samples during assay validation. Close collaboration between laboratory specialists and clinicians is essential to prevent overtreatment or undertreatment upon the implementation of novel analyzers or assays. Also, harmonization of TSB assays, with an emphasis on neonatal application, is warranted.

Hepatoprotective Effect of Moringa Oil on Rats under Fungicide Toxicity

The present study is designed to evaluate whether pretreatment with moringa would have a protective effect on thioacetamide (TAA)-induced liver fibrosis, assessing biochemical and histopathological changes in Wistar male rats. Exposure to TAA induced notable biochemical and histopathological alterations. Liver fibrosis induced by TAA, along with associated biochemical and histological damage, has not been previously investigated in male rats supplemented with moringa oil. The experiment involved forty male rats distributed across four groups, each comprising ten rats. Group 1 served as controls and received intraperitoneal injections of saline solution twice weekly for six weeks. Group 2 rats were injected with 300 mg/kg body weight of TAA (Sigma-Aldrich Corp.) twice weekly for the same duration. Group 3 rats were orally supplemented with moringa oil at 800 mg/kg body weight/day and received intraperitoneal injections of TAA at the same dosage as Group 2 for six weeks. Finally, Group 4 rats were injected with saline solution twice weekly and orally supplemented with moringa oil at 800 mg/kg body weight/day for the same period. At the end of the experiment, we determined body weight and performed liver function analysis. Additionally, we examined the liver histology of the different groups. Results showed that moringa oil treatment protected rat livers from TAA toxicity by improving liver function analysis and preventing liver fibrosis. Moringa oil can be considered a promising agent for protection against TAA toxicity.

Total bilirubin assay differences may cause inconsistent treatment decisions in neonatal hyperbilirubinaemia

OBJECTIVES

To assess interlaboratory variability of total serum bilirubin (TSB) results in newborns. Initiated following a clinical incident in which a neonate was transferred to a tertiary hospital for treatment of severe hyperbilirubinemia but on arrival was reclassified into a lower risk category due to a 20% difference in TSB between laboratories.

METHODS

Fresh residual plasma samples from hospital-born infants were pooled to obtain 11 samples across a range of total bilirubin concentrations. Aliquots were light-protected and measured on 7 commercial platforms at 4 accredited medical laboratories. Data from The Royal College of Pathologists of Australasia Quality Assurance Programs' (RCPAQAP) Neonatal Bilirubin program was analysed.

RESULTS

Twenty-four to 30% difference in results for individual samples, largely due to calibration differences between assays. When interpreted according to guidelines, results from different platforms would have led to different clinical interventions in some cases. RCPAQAP results showed significant within-method bias but were not shown to be commutable with patient samples.

CONCLUSIONS

There are clinically significant method-dependent differences in TSB results from neonatal samples, consistent with our clinical incident. The differences are largely due to lack of standardisation of calibrator values. This has implications for healthcare resource use and possibly for the neurodevelopment of infants. Intervention is needed at a number of levels, including clinical reporting of incidents arising from discordant results, commitment by manufacturers to ensure metrological traceability of methods with sufficiently low uncertainty in the final measurements, and availability of commutable quality assurance material to monitor assay performance, especially at the clinical decision points for neonatal jaundice.

Leveraging Predictive Pharmacometrics-Based Algorithms to Enhance Perinatal Care-Application to Neonatal Jaundice

The field of medicine is undergoing a fundamental change, transforming towards a modern data-driven patient-oriented approach. This paradigm shift also affects perinatal medicine as predictive algorithms and artificial intelligence are applied to enhance and individualize maternal, neonatal and perinatal care. Here, we introduce a pharmacometrics-based mathematical-statistical computer program (PMX-based algorithm) focusing on hyperbilirubinemia, a medical condition affecting half of all newborns. Independent datasets from two different centers consisting of total serum bilirubin measurements were utilized for model development (342 neonates, 1,478 bilirubin measurements) and validation (1,101 neonates, 3,081 bilirubin measurements), respectively. The mathematical-statistical structure of the PMX-based algorithm is a differential equation in the context of non-linear mixed effects modeling, together with Empirical Bayesian Estimation to predict bilirubin kinetics for a new patient. Several clinically relevant prediction scenarios were validated, i.e., prediction up to 24 h based on one bilirubin measurement, and prediction up to 48 h based on two bilirubin measurements. The PMX-based algorithm can be applied in two different clinical scenarios. First, bilirubin kinetics can be predicted up to 24 h based on one single bilirubin measurement with a median relative (absolute) prediction difference of 8.5% (median absolute prediction difference 17.4 μmol/l), and sensitivity and specificity of 95.7 and 96.3%, respectively. Second, bilirubin kinetics can be predicted up to 48 h based on two bilirubin measurements with a median relative (absolute) prediction difference of 9.2% (median absolute prediction difference 21.5 μmol/l), and sensitivity and specificity of 93.0 and 92.1%, respectively. In contrast to currently available nomogram-based static bilirubin stratification, the PMX-based algorithm presented here is a dynamic approach predicting individual bilirubin kinetics up to 48 h, an intelligent, predictive algorithm that can be incorporated in a clinical decision support tool. Such clinical decision support tools have the potential to benefit perinatal medicine facilitating personalized care of mothers and their born and unborn infants.

Analytical performance validation and clinical application of blood gas analyzer on the detection of neonatal bilirubin

BACKGROUND

It is not yet clear whether the trace blood gas analyzer can be used for biochemical detection of newborns. This study aimed to evaluate the reliability of the method for the detection of bilirubin in infants.

METHODS

Based on the Clinical and Laboratory Standards Institute (CLSI) EP15-A2 document, the analytical performance of the blood gas analyzer method for bilirubin detection in neonates was validated. The resulting data of 363 simultaneous bilirubin detection with blood gas analyzer (optical method) and biochemical analyzer (enzymatic method) were reviewed. According to the CLSI EP9-A3 document, the relevance and consistency of the measurement results were evaluated by Pearson correlation analysis, Passing-Bablok regression, and Bland-Altman deviation analysis.

RESULTS

The precision and accuracy of the Werfen GEM 4000 blood gas analyzer for the detection of different levels of bilirubin samples adhered to the manufacturer's statement and industry quality standards. The bilirubin detection values of the 2 methods showed a good correlation, and both of them were significantly correlated (P<0.001). Passing-Bablok regression results showed that the regression equation of the bilirubin detection value of the 2 methods is y = -21.00 + 1.17x, with the slope as 1.17 [95% confidence interval (CI): 1.15 to 1.19], and the intercept was -21.00 (95% CI: -23.62 to -18.71), the data of the 2 sets were not consistent in each concentration range. The Bland-Altman plot demonstrated that the bilirubin detection value of 16/363 cases (4.4%) for the 2 methods exceeded the 95% limits of agreement (95% LoA); of which the maximum bias was -30.34 (95% CI: -38.48 to -22.26) and there were 5/76 cases (6.6%) outside the 95% LoA in the >300 μmol/L group.

CONCLUSIONS

The method for detecting neonatal total bilirubin by trace blood gas analyzer basically meets the clinical requirements and can be used for the preliminary screening of neonatal jaundice. However, for severe hyperbilirubinemia that requires close monitoring of dynamics, a precise enzymatic quantification is required.

Neonatal hemoglobin affects the accuracy of whole blood bilirubin measurement on GEM Premier 4000 blood gas analyzers

Objectives

Whole blood bilirubin measured on blood gas analyzers is accepted by physicians in neonatal hyperbilirubinemia management since it requires a small sample volume. The accuracy of bilirubin measurement on blood gas analyzers is instrument dependent and remains controversial.

Design and Methods

Bilirubin in adult and umbilical cord whole blood samples, spiked with an unconjugated bilirubin standard, and non-spiked adult plasma samples was measured on a blood gas analyzer (GEM 4000) and a Core Laboratory Chemistry analyzer (Architect c16000) respectively. We also investigated the linear regression for neonatal and adult hemoglobin measured on the blood gas analyzer and the Core Laboratory hematology analyzer (Alinity h-Series).

Results

Plasma bilirubin measured on the blood gas analyzer and the chemistry analyzer was statistically identical. Adult whole blood bilirubin showed slightly increased proportional bias. When umbilical cord whole blood samples were used, the Deming regression showed GEM bilirubin =1.233(Architect) (95% CI 1.199 ~ 1.266)-44.43 ​μmol/L (95% CI -53.6 ​~ ​−35.2). The regression was significantly different from that in plasma (p ​< ​0.001) or adult whole blood (p ​< ​0.001) samples. 36.1% neonatal samples with bilirubin levels >50 ​μmol/L showed that the bias% was above laboratory standards. In addition, the regression of neonatal hemoglobin measurement between the GEM and the Alinity was significantly different from adult hemoglobin (p ​< ​0.01).

Conclusions

Neonatal whole blood bilirubin measurement on blood gas analyzers may be affected by neonatal hemoglobin. The method should be validated using neonatal whole blood samples or samples with a similar matrix before the analyzers are implemented into neonatal hyperbilirubinemia management.

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The bias of neonatal bilirubin measurements between the blood gas analyzer and the chemistry analyzer was investigated.

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Bilirubin in adult plasma and whole blood samples measured on the blood gas analyzer was comparable with the diazo assay.

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Bilirubin in umbilical cord whole blood samples measured on blood gas analyzer was not comparable with the diazo assay.

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In addition, the measurement of neonatal hemoglobin on the blood gas analyzer was not as accurate as adult hemoglobin.

Can bilirubin/albumin ratio predict neurodevelopmental outcome in severe neonatal hyperbilirubinemia? A 3-month follow up study

Background

The risk of kernicterus and BIND may be in part determined by total serum bilirubin (TSB) and by the level of non-albumin bound free bilirubin, which can easily pass the blood–brain barrier. Free bilirubin (Bf) seems a more reliable predictor for bilirubin neurotoxicity. Bilirubin/albumin ratio (B/A) is considered a surrogate parameter for Bf and has been more useful than TSB. The aim of the study is to determine whether B/A ratio correlates with BIND in newborns with severe hyperbilirubinemia and if it can predict poor neurologic outcome at 3 months follow up.

Results

This prospective study included one hundred seventeen outborn neonates ≥ 35 weeks admitted in a tertiary care neonatal intensive care unit, between May and December 2012, with TSB ≥ 20 mg/dl or necessitating exchange transfusion. Total serum bilirubin and serum albumin were done on admission and bilirubin/albumin ratio was calculated. BIND score was calculated. At the age of 3 months, 112 neonates were followed up with a detailed neurological assessment. Babies who depicted any abnormal motor examination were subjected to brain stem auditory evoked response and MRI examination. Seven infants (6.2%) presented with kernicterus on follow up. BIND scores on admission, mean TSB, and bilirubin/albumin ratio was significantly higher in kernicteric infants compared with those having normal neurological outcome at 3 months of age (P 0.001). The lowest TSB level at which kernicterus occurred in our study was 31 mg/dl. Receiver operation characteristics analysis identified B/A ratio cut off value for predicting kernicterus of 9.6 with sensitivity of 100% and specificity of 91.4%, whereas TSB cut off value of 30 mg/dl showed sensitivity of 100% and specificity of 83%.

Conclusion

B/A ratio is a strong indicator for the risk of kernicterus. B/A is more specific than TSB and should be used in the early management of neonatal hyperbilirubinemia.

Mechanism of bilirubin elimination in urine: insights and prospects for neonatal jaundice

Despite a century of research, bilirubin metabolism and the transport mechanisms responsible for homeostasis of bilirubin in serum remain controversial. Emerging evidence on the hepatic membrane transporters and inherited disorders of bilirubin metabolism have contributed to a greater understanding of the various steps involved in bilirubin homeostasis and its associated excretory pathways. We discuss these recent research findings on hepatic membrane transporters and evaluate their significance on the newborn bilirubin metabolism and excretion. New insights gained speculate that a proportion of conjugated bilirubin is excreted via the renal system, as an alternative to the intestinal excretion, even in normal physiological jaundice with no associated pathological concerns. Finally, this paper discusses the clinical relevance of targeting the altered renal excretory pathway, as bilirubin in urine may hold diagnostic importance in screening for neonatal jaundice.

Bilirubin estimates from smartphone images of newborn infants' skin correlated highly to serum bilirubin levels

AIM

Neonatal jaundice is an important cause of morbidity and mortality, and identifying the condition remains a challenge. This study evaluated a novel method of estimating bilirubin levels from colour-calibrated smartphone images.

METHODS

A cross-sectional prospective study was undertaken at two hospitals in Norway from February 2017 to March 2019, with standardised illumination at one hospital and non-standardised illumination at the other hospital. Healthy term-born infants with a normal birthweight were recruited up to 15 days of age. The main outcome measures were bilirubin estimates from digital images, plus total bilirubin in serum (TSB) and transcutaneous bilirubin (TcB).

RESULTS

Bilirubin estimates were performed for 302 newborn infants, and 76 had severe jaundice. The correlation between the smartphone estimates and TSB was measured by Pearson's r and was .84 for the whole sample. The correlation between the image estimates and TcB was 0.81. There were no significant differences between the hospitals. Sensitivity was 100%, and specificity was 69% for identifying severe jaundice of more than 250 µmol/L.

CONCLUSION

A smartphone-based tool that estimated bilirubin levels from digital images identified severe jaundice with high sensitivity and could provide a screening tool for neonatal jaundice.

Unbound bilirubin measurements in term and late-preterm infants

Background: Hyperbilirubinemia occurs in over 80% of newborns, and severe bilirubin toxicity can lead to neurological dysfunction and death. Unbound bilirubin (Bf) levels predict the risk of neurodevelopmental handicap, although total serum bilirubin (TSB) is used to manage care.Objective: To measure Bf levels in healthy infants, its relationship to TSB, and its response to phototherapy. We hypothesize unexpectedly high Bf levels, poor correlation with TSB and unpredictable response to phototherapy.Design/methods: Healthy infants were studied with simultaneous TSB and Bf measurements. The clinical data recorded included ethnicity, gender, birth weight, gestational age, and mode of delivery, Apgar scores, breast/formula feeds, and phototherapy.Results: One hundred thirty-two infants (3248.9 ± 509.2g, GA 38.7 ± 1.4 weeks), at mean age of the initial sample of 28.5 ± 15.6 h, had a TSB of 7.9 ± 2.7 mg/dl, and a Bf of 5.2 ± 3.2 nM. The correlation between Bf and TSB was significant but not between Bf and TSB for TSB >12 mg/dl. Bf >11nm were in 22.7% and >17 nM in 3.8% of infants. Post-phototherapy TSB and Bf levels were similar to those before treatment.Conclusions: The relationship between TSB and Bf in healthy infants is complex, with the inability of one to predict the other's level in infants with elevated TSB. The mechanism of bilirubin-related neurotoxicity suggests that the management of jaundice in healthy infants requires Bf measurements. Management of jaundice with TSB may result in more infants exposed to phototherapy. However, unexpected elevations of Bf occur in an apparently healthy population.

Newborns bilirubin concentration determined by different methods in relation to hematocrit and albumin level

Background

Monitoring of bilirubin is essential during early neonatal life. Bilirubin in high concentration is toxic to the brain and might cause irreversible neurological damage. Several different methods for bilirubin determination are available nowadays, but inconsistent results may be obtained. The study aimed to compare dry chemistry methods with vanadate oxidation method for bilirubin determination in relation to hematocrit and albumin level in neonates and infants.

Methods

The study included 98 consecutive serum samples from newborns and infants (47 boys and 51 girls, mean age 19 ± 15 days) treated in the University Children's Hospital in Krakow. Total bilirubin (TBil) and neonatal bilirubin (NBil) concentration were measured by dry chemistry analyser (Vitros 4600, Ortho Clinical Diagnostics Inc.). Total bilirubin (TBil_V) was also measured using vanadate oxidation method (Cormay, Poland). Albumin concentration and blood morphology have been routinely determined in all children.

Results

No significant differences between the mean value of NBil (69.00 ± 67.76 μmol/L), TBil (81.26 ± 70.13 μmol/L) and TBilV (75.90 ± 60.62 μmol/L) were noticed. High coefficient correlation between NBil and TBil as well as between NBil and TBil_V were noticed (Pearson's analysis, r = 0.99, r = 0.97, respectively; p < 0.0001 in both cases). There was a positive correlation between the difference (TBil_V - NBil) and hematocrit (p < 0.009, r = 0.2664).

Conclusions

In newborns and infants the same method for bilirubin determination should be used when the concentration of bilirubin is monitored. When using vanadate oxidation method for bilirubin determination, hematocrit value should be taken into account when results are interpreted.

The bilirubin albumin ratio in the management of hyperbilirubinemia in preterm infants to improve neurodevelopmental outcome: a randomized controlled trial--BARTrial

Background and Objective

High bilirubin/albumin (B/A) ratios increase the risk of bilirubin neurotoxicity. The B/A ratio may be a valuable measure, in addition to the total serum bilirubin (TSB), in the management of hyperbilirubinemia. We aimed to assess whether the additional use of B/A ratios in the management of hyperbilirubinemia in preterm infants improved neurodevelopmental outcome.

Methods

In a prospective, randomized controlled trial, 615 preterm infants of 32 weeks' gestation or less were randomly assigned to treatment based on either B/A ratio and TSB thresholds (consensus-based), whichever threshold was crossed first, or on the TSB thresholds only. The primary outcome was neurodevelopment at 18 to 24 months' corrected age as assessed with the Bayley Scales of Infant Development III by investigators unaware of treatment allocation. Secondary outcomes included complications of preterm birth and death.

Results

Composite motor (100±13 vs. 101±12) and cognitive (101±12 vs. 101±11) scores did not differ between the B/A ratio and TSB groups. Demographic characteristics, maximal TSB levels, B/A ratios, and other secondary outcomes were similar. The rates of death and/or severe neurodevelopmental impairment for the B/A ratio versus TSB groups were 15.4% versus 15.5% (P = 1.0) and 2.8% versus 1.4% (P = 0.62) for birth weights ≤1000 g and 1.8% versus 5.8% (P = 0.03) and 4.1% versus 2.0% (P = 0.26) for birth weights of >1000 g.

Conclusions

The additional use of B/A ratio in the management of hyperbilirubinemia in preterm infants did not improve their neurodevelopmental outcome.

Trial Registration

Controlled-Trials.com ISRCTN74465643