Correlation between transcutaneous and serum bilirubin in preterm infants before, during, and after phototherapy

Transcutaneous bilirubin reliability during and after phototherapy depending on skin color

Measurement of transcutaneous bilirubin (TcB) is a non-invasive, widely used technique to estimate serum bilirubin (SB). However, its reliability in multiethnic populations during and after phototherapy is still controversial even in covered skin. The aim of this study was to determine the reliability of TcB in covered (cTcB) and exposed (eTcB) skin during and after phototherapy in a multiethnic population of term and preterm neonates according to Neomar's neonatal skin color scale. Prospective, observational study comparing SB and TcB. We determined SB when clinically indicated and, at the same time, measured cTcB under a photo-opaque patch and eTcB next to it with a jaundice meter (Dräger JM-105TM). All dyads TcB-SB were compared, both globally and according to skin color. We obtained data from 200 newborns (color1: 44, color2: 111, color3: 41, color4: 4) and compared 296 dyads TcB/SB. Correlation between cTcB and SB is strong during (0.74-0.83) and after (0.79-0.88) phototherapy, both globally and by color group. The SB-cTcB bias depends on gestational age during phototherapy and on skin color following phototherapy. The correlation between eTcB and SB during phototherapy is not strong (0.54), but becomes so 12 h after discontinuing phototherapy (0.78).  Conclusions: Our study supports the reliability of cTcB to assess SB during and after phototherapy, with differences among skin tones after the treatment. The use of cTcB and Neomar's scale during and mainly after phototherapy may help reduce the number of blood samples required. What is Known: • Controversies exist on the reliability of jaundice meters during and after phototherapy in covered skin. Only a few studies have analyzed their accuracy in multiethnic populations, but none has used a validated neonatal skin color scale. What is New: • We verified correlation between serum and transcutaneous bilirubin in covered skin in a multiethnic population depending on skin color based on our own validated neonatal skin color scale during and after phototherapy.

Transcutaneous bilirubin levels in extremely preterm infants less than 30 weeks gestation

OBJECTIVE

The primary objective of this study was to determine the relationship between transcutaneous bilirubin (TcB) levels and total serum bilirubin (TSB) levels in extremely preterm infants.

STUDY DESIGN

We conducted a prospective multicenter study of extremely preterm infants less than 30 weeks gestation in California. Difference between paired TcB and TSB values were compared based on gestational age, birth weight, maternal race/ethnicity, chronological age as well as during and after phototherapy.

RESULTS

TSB values ranged from 0 to 12.6 mg/dl and the TcB values ranged from 0 to 14.2 mg/dl. TSB was predicted with a high degree of accuracy at TSB = 2.37 + 0.54 (TcB) with r = 0.786. There was good correlation across gestational age, birth weight, race/ethnic, chronological age subgroups as well as during and after phototherapy.

CONCLUSION

Our study supports the use of TcB as a screening tool for monitoring jaundice in extremely preterm infants.

A Prospective Comparison of Serum and Transcutaneous Bilirubin in Indian Neonates

The objective of this study was to compare the transcutaneous bilirubin (TcB) with total serum bilirubin (TSB) and to find out the effect of phototherapy on correlation of TcB and TSB during and after phototherapy in Indian neonates. Prospective observational study was performed at neonatal intensive care unit of Uttar Pradesh University of Medical Sciences, Saifai, Etawah, India. Blood samples for TSB estimation of 276 jaundiced neonates were sent, and simultaneously, TcB was measured at forehead and sternum on admission and 12 hourly till discontinuation of phototherapy as per the American Academy of Pediatrics nomogram chart and their correlation was assessed. The effect of phototherapy on correlation of TcB and TSB during and after phototherapy was also observed. The correlation between TSB and TcB was linear and significant for the entire study population over forehead (Pearson's r  = 0.802, R ²  = 0.644, p  < 0.001) as well as over sternum (Pearson's r  = 0.825, R ²  = 0.681, p  < 0.001) before starting the phototherapy. This correlation becomes slightly lower for TSB versus TcB forehead (Pearson's r  = 0.753, R ²  = 0.568, p  < 0.001) and for TSB versus TcB sternum (Pearson's r  = 0.754, R ²  = 0.569, p  < 0.001) after giving phototherapy for at least 24 hours. The correlation coefficients for TSB versus TcB measurements over forehead and sternum were 0.758 and 0.806, respectively, after 36 hours of phototherapy. TcB measurements using the transcutaneous bilirubinometer correlate closely with TSB levels, so it can be used as an easy and rapid noninvasive method of bilirubin measurement in jaundiced neonates.

Efficacy of transcutaneous bilirubinometry as compared to serum bilirubin in preterm newborn during phototherapy

Transcutaneous measurement of bilirubin is being used for neonatal jaundice. Its utility during phototherapy in preterm babies is not established. The objective of our study was to assess the efficacy of transcutaneous bilirubin (TcB) measurement in comparison to total serum bilirubin in preterm newborns at admission and during phototherapy at the covered skin area (glabella). It was a prospective observational study and conducted at the neonatal intensive care unit of a tertiary care hospital from January 2017 to January 2019. One hundred eligible preterm neonates were enrolled. Babies who were very sick, with poor peripheral circulation, edematous, having conjugated hyperbilirubinemia, with major congenital malformations, already received phototherapy or exchange transfusion were excluded. Paired total serum bilirubin and transcutaneous bilirubin were measured at admission and 6 h and 24 h during phototherapy. TcB was measured from the area (glabella) covered by an eye protector during phototherapy. The sample for TsB was taken within 10 min of TcB measurement. The mean differences between TsB and TcB values at admission and 6 h and 24 h of phototherapy were - 0.005 (0.353) mg/dl, - 0.350 (0.611) mg/dl, and - 0.592 (0.353) mg/dl, respectively. At admission or before starting of phototherapy, the difference (TsB-TcB) was statistically not significant (p = .125), while the difference in these values was statistically significant at 6 h and 24 h of phototherapy.Conclusion: TcB measurements from the covered skin area in jaundiced preterm infants during phototherapy were not correlated with TsB and cannot be used as an alternate of serum bilirubin testing. What is known • HPLC bilirubin measurement is a gold standard test for bilirubin measurement but impractical for day to day use. Serum total bilirubin is used for clinical testing.. • There is evidence for use of transcutaneous bilirubinometry for assessment of bilirubin in term newborn. What is new • TcB measurements from a covered skin area in jaundiced preterm newborns under phototherapy were not correlated significantly at 6 h and 24 h of phototherapy, but correlated before phototherapy. • TcB cannot be used as an alternate of serum bilirubin testing in preterm infants during phototherapy.

Screening methods for neonatal hyperbilirubinemia: benefits, limitations, requirements, and novel developments

Severe neonatal hyperbilirubinemia (SNH) is a serious condition that occurs worldwide. Timely recognition with bilirubin determination is key in the management of SNH. Visual assessment of jaundice is unreliable. Fortunately, transcutaneous bilirubin measurement for screening newborn infants is routinely available in many hospitals and outpatient settings. Despite a few limitations, the use of transcutaneous devices facilitates early recognition and appropriate management of neonatal jaundice. Unfortunately, however, advanced and often costly screening modalities are not accessible to everyone, while there is an urgent need for inexpensive yet accurate instruments to assess total serum bilirubin (TSB). In the near future, novel icterometers, and in particular optical bilirubin estimates obtained with a smartphone camera and processed with a smartphone application (app), seem promising methods for screening for SNH. If proven reliable, these methods may empower outpatient health workers as well as parents at home to detect jaundice using a simple portable device. Successful implementation of ubiquitous bilirubin screening may contribute substantially to the reduction of the worldwide burden of SNH. The benefits of non-invasive bilirubin screening notwithstanding, any bilirubin determination obtained through non-invasive screening must be confirmed by a diagnostic method before treatment. IMPACT: Key message: Screening methods for neonatal hyperbilirubinemia facilitate early recognition and timely treatment of severe neonatal hyperbilirubinemia (SNH). Any bilirubin screening result obtained must be confirmed by a diagnostic method. What does this article add to the existing literature? Data on optical bilirubin estimation are summarized. Niche research strategies for prevention of SNH are presented. Impact: Transcutaneous screening for neonatal hyperbilirubinemia contributes to the prevention of SNH. A smartphone application with optical bilirubin estimation seems a promising low-cost screening method, especially in low-resource settings or at home.

Comparing JM-105 and MBJ-20 Transcutaneous Bilirubinometers According to the Area Tested in Ethnically Diverse Late-Preterm and Term Neonates

This study aims to evaluate the correlation between the results of transcutaneous bilirubin (TcB) levels measured by the 2 transcutaneous bilirubinometers according to the area tested and to compare the TcB measurements and the serum bilirubin (SBR) levels. We screened 78 neonates born at more than 35 weeks of gestation and aged less than 168 hours for jaundice. We used JM-105 and MBJ-20 to measure the TcB at the forehead and the chest. For newborns who had high TcB measurements, we obtained blood samples during the subsequent 30 minutes. There was a strong correlation between the TcB measurements by JM-105 and MBJ-20 and this correlation was stronger when they were used on the sternum. The mean differences between the TcB measurements on the forehead and the sternum and the SBR levels were similar for the JM-105 and the MBJ-20. There was a strong correlation between SBR and the measurements using the 2 devices on the sternum (JM-105: r = 0.805; MBJ-20: r = 0.801), unlike measurements taken on the forehead by each device (r = 0.777 and r = 0.751, respectively). Both devices had high sensitivity and negative predictive values at SBR level of less than 230 μmol/L (<13.4 mg/dL) and high specificity and positive predictive values at SBR level of 230 μmol/L and greater (>13.4mg/dL). Both devices equally overestimated the actual SBR and had more reliable results if used on the sternum.

Transcutaneous Bilirubin Monitoring in Preterm Infants of 23 to 34 Weeks' Gestation

OBJECTIVE

 The study aimed to evaluate the validity of transcutaneous bilirubin (TcB) measurements at three sites in premature infants born at 23^0/7 to 34^6/7 weeks' gestational age (GA) compared with total serum bilirubin (TSB) measurements.

STUDY DESIGN

 A prospective study was conducted at Banner - University Medical Center Phoenix, where informed consent was obtained from the infant's parent or legally authorized representative. Cohort A was comprised of infants 23^0/7 to 28^6/7 weeks' GA and Cohort B contained subjects 29^0/7 to 34^6/7 weeks' GA. Baseline TSB measurements were collected at approximately 24 hours of life, as the standard of care and the TcB measurements were obtained from the sternum, interscapular, and buttock areas at approximately ± 30 minutes from collection of the TSB. Statistical analysis of measurements including sensitivity, specificity, positive, and negative predictive values, and the area under the receiver operator characteristic curve (AUROC) were performed.

RESULTS

 A total of 166 infants were included in the study population. Cohort A consisted of 41 subjects and Cohort B contained 125 subjects. The results showed that baseline TcB measurements from the interscapular area were the most sensitive and specific with TSB levels >5.0 mg/dL in Cohort A. Baseline TcB measurements from the sternum demonstrated greatest sensitivity and specificity when the TSB level was >8.0 mg/dL in Cohort B. In general, each of the three sites in both cohorts demonstrated excellent AUROCs and negative predictive values.

CONCLUSION

 The use of a TcB meter in preterm infants can be a reliable noninvasive screening tool for hyperbilirubinemia, and it may be beneficial in decreasing painful stimuli and iatrogenic blood loss when used as an adjunct to TSB monitoring.

KEY POINTS

· Interscapular TcB is sensitive/specific in 23 to 29 weeks' GA.. · Sternal TcB is sensitive/specific in 29 to 35 weeks' GA.. · TcB readings are reliable in preterm infants.. · TcB is reliable when serum bilirubin is >5.0 mg/dL..

Reliability of transcutaneous bilirubin determination based on skin color determined by a neonatal skin color scale of our own

Measurement of transcutaneous bilirubin (TcB) is widely used to estimate serum bilirubin (SB). However, its reliability depending on skin tone is still controversial. Ethnic classification does not correlate well with skin tone. We aimed to determine the reliability of transcutaneous bilirubin in a multiethnic population based on skin color according to our neonatal skin color scale. We conducted a prospective, observational study comparing SB and TcB among different skin colors. With the blood sample routinely obtained at 48-72 h for the screening of inborn errors of metabolism, we determined SB and TcB with a jaundice meter. We obtained data from 1359 newborns (color 1 337, color 2 750, color 3 249, color 4 23) and analyzed 1549 dyads SB/TcB. Correlation between TcB and serum bilirubin was very good (R² = 0.908-0.956), globally and by color group, with slight differences between darker and lighter skin colors. Bland-Altman plots showed different mean bias depending on skin color. Conclusions: Our study not only supports the reliability of TcB to assess SB regardless of skin color, but also supports the fact that TcB tends to overestimate SB in a higher degree in dark-skinned neonates. This may help reduce the number of blood samples for newborns. What is Known: • Jaundice meters are extensively used to diagnose neonatal hyperbilirubinemia, although controversies exist on their reliability depending on skin color. • Only a few studies have analyzed their accuracy in multiethnic populations, but none has used a validated neonatal skin color scale. What is New: • We verified correlation between serum and transcutaneous bilirubin in a multiethnic population depending on skin color after classifying our neonates into color groups with our own validated neonatal skin color scale.

Accuracy of Transcutaneous Bilirubin Versus Serum Bilirubin Measurement in Preterm Infants Receiving Phototherapy: A Systematic Review

BACKGROUND

Jaundice is a common condition among preterm infants in the neonatal intensive care unit (NICU). Total serum bilirubin (TSB) offers a gold standard tool for measurement, but blood sampling can be costly, time-consuming, and not without risks of infection and pain. Transcutaneous bilimeter (TcB) allows for noninvasive assessment of bilirubin. However, due to questions of accuracy the use of the TcB in preterm infants receiving phototherapy has not been widely adapted in the NICU.

PURPOSE

To systematically review studies that measure TcB versus TSB bilirubin in preterm infants who are receiving phototherapy.

METHODS

A systematic electronic search of databases (CINAHL, EMBASE, Cochrane, Medline, PubMed) was completed for English language publications. No date limitation was placed on the search. Inclusion criteria were based on preterm infants that were in the NICU receiving or had recently received phototherapy.

RESULTS

Nine studies of different quantitative study designs were reviewed. A good to strong correlation between TcB and TSB in preterm infants receiving phototherapy was demonstrated. There was a stronger correlation found in studies that examined TcB in unexposed skin areas during phototherapy.

IMPLICATIONS FOR PRACTICE

TcB may allow for a reduction in blood sampling, which would reduce painful procedures, reduce the risk of infection and anemia resulting from repeated blood sampling. It also acts as a more time and cost-efficient measurement tool.

IMPLICATIONS FOR RESEARCH

Larger scaled quantitative studies on the accuracy of TcB in preterm infants receiving phototherapy are needed to provide more evidence-based data and guide clinical practice on this topic.

Large scale validation of a new non-invasive and non-contact bilirubinometer in neonates with risk factors

The study was aimed to evaluate the performance of a newly developed non-invasive and non-contact bilirubin measurement device (AJO-Neo) as an alternative to the conventional invasive biochemical method of total serum bilirubin (TSB) estimation in preterm and term neonates suffering from hyperbilirubinemia associated with risk factors, and/or undergoing phototherapy. The safety and efficacy of the device were assessed in 1968 neonates with gestational ages ranging from 28 to 41 weeks and suffering from incidences of hyperbilirubinemia. Linear regression analysis showed a good correlation between AJO-Neo and the conventional method of TSB (Pearson’s coefficient, r = 0.79). The small bias (0.27 mg/dL) and limits of agreements (− 3.44 to 3.99 mg/dL) were within the range of clinical acceptance. The device was also precise in the measurement of bilirubin levels in all subgroups of the study. The receiver operator curve (ROC), that takes account of both sensitivity and specificity of a device showed high efficacy of the device (area under the curve, AUC = 0.83) in the detection of bilirubin. While monitoring the bilirubin level during phototherapy, the device indicated promising results showing good agreement with TSB. Specificities and sensitivities of the device indicated a much higher accuracy in neonates with associated risk factors for hyperbilirubinemia. Hence, the newly developed device (AJO-Neo) is reliable in measuring bilirubin level in preterm, and term neonates irrespective of gestational or postnatal age, sex, risk factors, feeding behavior or skin color.

Accuracy of transcutaneous bilirubin on covered skin in preterm and term newborns receiving phototherapy using a JM-105 bilirubinometer

OBJECTIVE

Determine the suitability of transcutaneous bilirubin (TCB) as a tool to assess the effectiveness of phototherapy on patched skin.

STUDY DESIGN

A prospective observational study was conducted. We covered a fragment of skin (sternum) with a photo-opaque patch. Several simultaneous TCB and TSB measurements were performed with the JM-105 bilirubinometer. Bland and Altman test evaluated the agreement between bilirubin levels.

RESULT

A total of 217 patients were studied, 48.8% were preterm. The mean difference between TSB and TCB before the start of treatment was 1.07 mg/dL. During phototherapy, differences on covered skin were 0.52, 0.27, and 0.39 mg/dL at 24, 48, and 72 h of therapy respectively. The best correlation was observed at 48 h in preterm infants.

CONCLUSION

The measurement of TCB on patched skin (PTCB) is useful for monitoring the response to phototherapy in term and preterm infants. We use a patch with a removable flap that eases successive measures without disturbing the patients.

Transcutaneous bilirubinometry during and after phototherapy in preterm infants: a prospective observational study

OBJECTIVE

To examine the accuracy of transcutaneous bilirubinometry (TCB) measurements during and after phototherapy (PT) in preterm infants.

DESIGN

Prospective observational cohort study.

SETTING

Level III neonatal centre.

PATIENTS

Preterm infants (from 23+0 to 36+6 weeks of gestation) born between June 2017 and May 2018 requiring PT.

INTERVENTIONS

TCB was measured from an exposed area of the skin (the sternum; TCBU) and the covered area of the skin under the nappy (the bony part of the upper outer quadrant of the buttock; TCBC) within an hour of obtaining total serum bilirubin (TSB).

MAIN OUTCOME MEASURES

Correlation and agreement between TCB (TCBU and TCBC) and TSB during and after PT.

RESULTS

We have enrolled 196 preterm infants. There was a significant correlation between TSB and TCB during PT (r=0.72, 95% CI 0.66 to 0.77 in covered area; r=0.75, 95% CI 0.70 to 0.80 in uncovered area) and after PT (r=0.87, 95% CI 0.83 to 0.91). TCB underestimated TSB level during PT, with a mean TCBC-TSB difference of -25±43 (95% agreement limits of 62 to -112) and a mean TCBU-TSB difference of -48±46 (95% agreement limits of 45 to -140). The agreement between TCB and TSB after cessation of PT improved, with TCB underestimating TSB by a mean TCB-TSB difference of -10±31 (95% agreement limits of 52 to -72).

CONCLUSION

TCB measurements correlated strongly with TSB levels during and after PT. However, there was a wide and clinically relevant disagreement between TCB and TSB measurements during the PT phase, improving significantly after PT.

Should transcutaneous bilirubin be measured in preterm infants receiving phototherapy? The relationship between transcutaneous and total serum bilirubin in preterm infants with and without phototherapy

Our objective was to analyze the relationship between transcutaneous bilirubin (TcB) measured on an unexposed area of skin and total serum bilirubin (TSB) in preterm infants before, during, and after phototherapy (PT). For this purpose paired TSB and TcB levels were measured daily during the first ten days after birth in preterm infants of less than 32 weeks’ gestation. TcB was measured with a Dräger Jaundice Meter JM-103 on the covered hipbone. Agreement between TSB and TcB levels was assessed before, during, and after PT. True negative and corresponding false negative percentages were calculated using different TcB cut-off levels. Data are presented as mean (±SD). We obtained 856 paired TcB and TSB levels in 109 preterm infants (66 boys, gestational age 29.4 ± 1.6 weeks and birth weight 1282 g ± 316 g). We found that the difference between TSB and TcB before PT was significantly lower, 44 (±36) μmol/L, than the difference during and after PT, 61 (±29) μmol/L and 63 (±25) μmol/L, respectively; P < 0.01. Blood sampling could be reduced by 42%, with 2% false negatives, when 50 μmol/L was added to the TcB level at 70% of the PT threshold. Our conclusion is that phototherapy enhances underestimation of TSB by TcB in preterms, even if measured on unexposed skin. The use of specific TcB cut-off levels substantially reduces the need for TSB measurements.