Transcutaneous bilirubinometer: Its use in Chinese term infants and the effect of haematocrit and phototherapy on the TcB index

The application of the transcutaneous bilirubinometer in screening for neonatal jaundice was evaluated in 259 full-term Chinese infants: 202 who had not received any treatment and 57 who were receiving phototherapy. The transcutaneous bilirubin index correlated well with the serum bilirubin level (SB) of the untreated infants and the coefficient of correlation was slightly higher for TcB readings obtained over the mid-sternal area ( r =0.91; P <0.001) than those over the forehead ( r =0.85; P <0.001). Transcutaneous bilirubinometry was unreliable in predicting the SB level in infants receiving phototherapy even if the SB readings were obtained over shaded skin. The haematocrit of the infants, though having a statistically significant effect on the TcB index, contributed only minimally to the regression line and correlation coefficient between the TcB index and SB level.     

Transcutaneous bilirubinometer: its use in Chinese term infants and the effect of haematocrit and phototherapy on the TcB index

The application of the transcutaneous bilirubinometer in screening for neonatal jaundice was evaluated in 259 full-term Chinese infants: 202 who had not received any treatment and 57 who were receiving phototherapy. The transcutaneous bilirubin index correlated well with the serum bilirubin level (SB) of the untreated infants and the coefficient of correlation was slightly higher for TcB readings obtained over the mid-sternal area (r = 0.91; P less than 0.001) than those over the forehead (r = 0.85; P less than 0.001). Transcutaneous bilirubinometry was unreliable in predicting the SB level in infants receiving phototherapy even if the SB readings were obtained over shaded skin. The haematocrit of the infants, though having a statistically significant effect on the TcB index, contributed only minimally to the regression line and correlation coefficient between the TcB index and SB level.     

Transcutaneous bilirubinometry. Evaluation of accuracy and reliability in a large population

A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breast-fed newborn infants during the first twelve days of life. Our present study revealed that transcutaneous bilirubin measurements obtained from the forehead, chest, and sternum correlated well with serum bilirubin concentrations measured by AO bilirubinometer (0.910-0.922, p less than 0.001, n = 576). The 95% confidence limits were +/- 3.04 mg/dl for the forehead, +/- 2.85 mg/dl for the chest, and +/- 2.84 mg/dl for the sternum readings. The overall mean of values from the forehead, chest and sternum, when compared with individual means, was found to correlate better with serum bilirubin concentrations (r = 0.930, p less than 0.001, n = 576) and improve the 95% confidence limits to +/- 2.68 mg/dl. These results demonstrated that the accuracy and reliability of TcB measurement could be increased further with multiple site measurement. The study clearly indicates that transcutaneous bilirubinometry is useful for clinical screening of serum bilirubin levels in Japanese full-term newborn infants.     

Transcutaneous Bilirubinometry

ABSTRACT. A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breast-fed newborn infants during the first twelve days of life. Our present study revealed that transcutaneous bilirubin measurements obtained from the forehead, chest, and sternum correlated well with serum bilirubin concentrations measured by AO bilirubinometer (0.910–0.922, p <0.001, n =576). The 95% confidence lmits were ±3.04 mg/dl for the forehead, ±2.85 mg/dl for the chest, and ±2.84 mg/dl for the sternum readings. The overall mean of values from the forehead, chest and sternum, when compared with individual means, was found to correlate better with serum bilirubin concentrations ( r =0.930, p <0.001, n =576) and improve the 95% confidence limits to ±2.68 mg/dl. These results demonstrated that the accuracy and reliability of TcB measurement could be increased further with multiple site measurement. The study clearly indicates that transcutaneous bilirubinometry is useful for clinical screening of serum bilirubin levels in Japanese full-term newborn infants.     

Skin bilirubin measurement during phototherapy in preterm and term newborn infants

Background

The few existing studies evaluating the reliability of transcutaneous bilirubin monitoring during phototherapy gave controversial results.

Aims

To evaluate the accuracy of transcutaneous bilirubin measurement in a large population of newborn infants, during phototherapy.

Study design and methods

Total serum bilirubin and transcutaneous bilirubin on patched and unpatched skin areas were simultaneously measured in newborn infants undergoing phototherapy. Transcutaneous measurements were performed with a multiwavelength transcutaneous bilirubinometer (Respironics BiliCheck™). The Passing-Bablok regression and the Bland-Altman plot were used to estimate the relationship between serum and transcutaneous bilirubin.

Results

We studied 364 newborn infants with a mean (SD) gestational age of 34.6 (3) weeks and a mean birth weight of 2371 (805) grams. Total serum bilirubin, patched transcutaneous bilirubin and unpatched transcutaneous bilirubin were similar before phototherapy. After 52 (33) hours of phototherapy, the difference between serum bilirubin and patched transcutaneous bilirubin was 0.2 (3.1) mg/dL (not significant) while the difference between serum bilirubin and unpatched transcutaneous bilirubin was 3.2 (3.0) mg/dL (p < 0.001). Statistical analysis showed a good agreement between serum bilirubin and patched transcutaneous bilirubin, while unpatched transcutaneous bilirubin underestimates serum levels. The difference between patched and unpatched values was significantly lower in preterm than in term infants (2.8 mg/dL vs. 3.6 mg/dL; p < 0.001).

Conclusion

BiliCheck can be safely used for the evaluation of bilirubin levels in newborn infants under phototherapy. Its reliability on patched skin of the forehead is high enough to consistently reduce blood draws and to ascertain when to discontinue phototherapy. Because of the individual variance, any clinical decision has to be taken on the basis of the transcutaneous bilirubin trend more than on a single value.     

Transcutaneous bilirubinometry: an evaluation.

The transcutaneous bilirubinometer was evaluated in 60 term and 10 preterm infants. A significant correlation was found between the transcutaneous index and the total serum bilirubin concentration for both term and preterm infants. The reliability of the transcutaneous bilirubinometer as a screening method was confirmed, and index criteria for serum bilirubin analysis have been suggested for term babies. The instrument was precise and accurate and the method both noninvasive and atraumatic. Since individual serum bilirubin levels and the transcutaneous index may correlate poorly the transcutaneous method cannot replace traditional serum bilirubin estimation.     

Comparison of transcutaneous bilirubin measurement with total serum bilirubin levels in preterm neonates receiving phototherapy

Objective

To compare transcutaneous bilirubin with total serum bilirubin in preterm neonates after initiation of phototherapy.

Methods

Jaundice was assessed in 30 preterm neonates with transcutaneous bilirubin and total serum bilirubin before initiation of phototherapy and at 12 hr after initiation of phototherapy. A photo-occlusive patch was applied over the sternum.

Results

Transcutaneous bilirubin has a good correlation with total serum bilirubin after initiation of phototherapy. (r=0.918, P<0.001). Transcutaneous bilirubin at 28-32 weeks of gestation (r = 0.97) was better correlated with total serum bilirubin than those at 32-37 weeks (r =0.88). The correlation was better for neonates <72 hours old (r = 0.96) than those >72 hours of age (r = 0.82).

Conclusion

Transcutaneous bilirubin correlates significantly with total serum bilirubin at the patched sternal site after initiation of phototherapy in preterm neonates.

     

Multiple site readings from a transcutaneous bilirubinometer

ABSTRACT. The Transcutaneous Bilirubinometer was evaluated on 95 occasions on 66 infants who were clinically jaundiced but not receiving phototherapy. Meter readings were obtained from seven different body sites within 30 minutes of sampling blood for serum bilirubin estimation. A cephalocaudal progression of dermal icterus was demonstrated. Meter readings from forehead, sternum, thigh, upper and lower back correlated closely with serum bilirubin (r ≧ .93). The 95% confidence limits for forehead and sternum were ± 52.8 μmol/l. Multiple regression analysis using all 7 body sites increased the correlation coefficient to .97 and decreased the confidence limits to 44.4 μmol/l. However, we would recommend the forehead and sternum as the most reliable sites for meter readings with acceptable accuracy and precision. Meter readings from preterm and low birth weight babies tend to over-estimate serum bilirubin. Further Australian studies are necessary to establish regression lines for infants of different racial backgrounds.     

TRANSCUTANEOUS BILIRUBINOMETRY IN FULLTERM CHINESE AND MALAY INFANTS

ABSTRACT. An evaluation of the Minolta/Airshields transcutaneous bilirubin meter (TcB) was made in 68 Chinese and 28 Malay fullterm infants and 9 infants undergoing phototherapy. A close correlation between the TcB index and bilirubin values was achieved at all three sites measured–forehead, sternum and back. The accuracy of the TcB was reduced by phototherapy. A high degree of reproducibility was demonstrated. The TcB is a useful screening device for neonatal jaundice.     

Assessment of jaundice in preterm neonates: comparison between clinical assessment, two transcutaneous bilirubinometers and serum bilirubin values

Aim: 1) To compare the clinical assessment of craniocaudal progression of jaundice and two transcutaneous bilirubinometers with serum bilirubin values in preterm neonates; 2) to identify factors affecting the difference between non-invasive bilirubin estimation and serum bilirubin. Methods: Serum bilirubin was clinically estimated in healthy preterm newborn infants (34 to 36.9 gestational weeks) independently by a primary investigator and by nurses, and subsequently compared with separate measures of two transcutaneous bilirubinometers. Results: A total of 107 measurements were performed on 69 infants. Minolta JM-102 showed the best performance, with ROC area under the curve of 0.96, followed by BiliCheck™ over the sternum (0.89) and over the forehead (0.88), clinical assessment by nurses (0.73) and by a physician (0.70). Serum bilirubin >190 μmol/l can be detected with 95% sensitivity with Minolta JM-102 ≥19 units, with BiliCheck™ ≥145 μmol/l over the sternum and ≥165 μmol/l over the forehead and with jaundice progression to the trunk or further (Kramer zone ≥2). Gestational age affects all non-invasive methods in the estimation of serum bilirubin, whereas skin colour affects both BiliCheck™ and clinical assessment. Ambient light affects only clinical assessment.

Conclusion: Minolta JM-102 showed the best performance, closely followed by BiliCheck™, with clinical assessment performing far worse than either transcutaneous method. None of the three methods are recommended as complete substitutes for serum bilirubin values in jaundiced preterm infants.     

The accuracy of transcutaneous bilirubin measurements in neonates: a correlation study

A prospective observational study was conducted on 212 neonates born between 24 and 42 weeks of gestation who required blood sampling to determine total serum bilirubin (TSB) in the first week of life, prior to phototherapy. The transcutaneous bilirubin (TcB) measurements were performed on the infant's forehead using BiliCheck within +/-30 min of a blood sample being drawn. There was significant (r = 0.78) correlation between bilirubin levels obtained transcutaneously and those measured in the infant's blood. The correlation was not affected by birth weight and was dependent on the bilirubin levels. The negative nonsignificant correlation appears when TSB levels are greater than 11 mg/dl. Thus, TcB measurements can accurately predict TSB values lower than 11 mg/dl in a multiracial preterm and term neonatal population.     

Prediction of severe hyperbilirubinaemia using the Bilicheck transcutaneous bilirubinometer

OBJECTIVES: To determine the sensitivity and specificity of different levels of bilirubin measured by the transcutaneous bilirubinometer Bilicheck on forehead and sternum for predicting severe hyperbilirubinaemia of total serum bilirubin (TSB)>or=300 micromol/L in Malay, Chinese and Indian infants. DESIGN: A prospective observational study. SETTING: A tertiary care University hospital. METHODS: A total of 345 healthy jaundiced term infants were recruited prior to commencement of phototherapy or exchange transfusion. Transcutaneous bilirubin (TcB) level was measured with the Bilicheck from infants' foreheads (TcBh) and sternums (TcBs) within 30 min of serum bilirubin measurement by the diazo method in the hospital laboratory. RESULTS: The median serum TSB level of these infants was 233.0 micromol/L (range: 108.0-589.0). Ninety-five (27.5%) infants had TSB>or=300 micromol/L. There was good correlation between log10TSB and TcB measured from the forehead (r=0.80, P<0.0001) and the sternum (r=0.86, P<0.0001). At TcBh cut-off of 250 micromol/L, the Bilicheck detected TSB>or=300 micromol/L with a sensitivity of 100% and a specificity of 39.2%, the area under the receiver operative characteristic curve being 0.89 (95% confidence interval 0.85, 0.92). At TcBs cut-off of 200 micromol/L, the Bilicheck detected TSB>or=300 micromol/L with a sensitivity of 100% and a specificity of 33.6%, the area under receiver operative characteristic curve being 0.93 (95% confidence interval 0.90, 0.96). CONCLUSION: The Bilicheck is not a substitute for measuring serum bilirubin. However, using predetermined TcB cut-off values with reasonable sensitivity and specificity, it is a useful screening tool to identify infants with TSB>or=300 micromol/L requiring blood sampling, hospital admission and treatment.     

Transcutaneous bilirubinometry. III. Dermal bilirubin kinetics under green and blue light phototherapy

Using the transcutaneous bilirubinometer, we studied the response of cutaneous bilirubin to different colors of light during phototherapy. Three groups of ten infants were exposed to blue, green, and blue-green lights at a mean postnatal age ranging from 50 to 77 hours. Patched areas served as controls. Every 15 minutes during four hours of phototherapy, we obtained simultaneous measurements from exposed and covered areas. After the onset of phototherapy, transcutaneous bilirubinometer values from the covered areas in all groups remained stable. The overall rate of bleaching was lowest in the green light group and highest in the blue-green combination group. In this group of infants, green light appeared to enhance the effectiveness of blue light in reducing dermal bilirubin concentrations as measured by the transcutaneous bilirubinometer.     

Transcutaneous bilirubinometry during and after phototherapy

AIM: To evaluate the reliability of transcutaneous bilirubinometry (TcB) during and after phototherapy. METHODS: TcB was performed on the forehead and chest of infants with neonatal jaundice when capillary blood was sampled for bilirubin determination in a control group of 240 neonates. In a second group of 70 neonates exposed to phototherapy the same procedure was performed after at least 24 h of exposure: on the forehead, TcB was done in the centre of the unexposed area and also on the adjacent exposed area, and the exposed chest. During the post-phototherapy period, TcB was again done during the first and second days, at least 18-24 h after cessation of phototherapy. The results were then statistically evaluated and regression curves were plotted. RESULTS: A close correlation between TcB values and bilirubin levels was observed in the control group. In the phototherapy group, a correlation was also found between the TcB and the bilirubin values, but this correlation was significantly poorer than that of the controls; the correlation for the covered part of the forehead was significantly better than that of the exposed part but still poorer than that of the controls, though the difference was no longer significant. Skin colour recovered during the post-phototherapy period and correlation was better than that during exposure and no longer significantly different from that of the controls. CONCLUSION: Through its bleaching effect on the skin, phototherapy affects the correlation between TcB and the bilirubin values, but does not totally eliminate it. The unexposed parts show a better correlation, though this was still poorer than that of the controls. Recovery of skin colour occurred within 18-24 h after cessation of exposure.     

Transcutaneous bilirubinometry in Chinese, Malay and Indian infants

The objective of this study was to investigate the correlation of transcutaneous bilirubinometry (TcB) and plasma bilirubin concentrations in full-term Chinese, Malay and Indian infants. TcB was performed with the Minolta Airshields bilirubinometer on Chinese, Malay and Indian full-term infants. The readings were taken on the chest (sternum) and forehead (glabella) when capillary blood was sampled for bilirubin determination. Five hundred and forty TcB indices in 253 Chinese infants, 282 in 169 Malay infants, and 182 in 120 Indian infants were obtained over the sternum and forehead. A good correlation between the TcB indices and the bilirubin concentrations was observed in Chinese, Malay and Indian infants: r = 0.78 (chest), r = 0.73 (forehead); r = 0.86 (chest), r = 0.84 (forehead); and r = 0.84 (chest), r = 0.82 (forehead). The correlation was just as good when the combined values were evaluated together: r = 0.80 (chest) r = 0.75 (forehead). In Chinese infants, correlation at values below 250 μmol ⁻¹ was significantly better than that at values over 250μmoll⁻¹ r = 0.80 versus r =−0.20, < 0.00001 (chest), and r = 0.74 versus r = 0.07, < 0.00001 (forehead). However, a safer cut-off point clinically would be 200 μmoll⁻¹, since only relatively few higher bilirubin values were encountered when TcB indices were below 200 μmoll⁻¹ The same pattern was noticed with the other two groups, and the combined group. Thus, TcB provides a non-invasive, cost-effective screening method for significant neonatal jaundice, sparing infants and parents physical and emotional stress, and medical and nursing personnel extra work and inconvenience.     

Transcutaneous bilirubin measurement in evaluating neonatal jaundice among Saudi newborns

Transcutaneous bilirubin measurements, using the Minolta transcutaneous bilirubinometer (TcB), were performed in 68 full-term, healthy Saudi infants. Infants who had exchange transfusion and those under phototherapy were excluded. One hundred and twenty measurements were obtained and compared with serum bilirubin levels measured by the American Optics (A.O.) bilirubinometer. The serum bilirubin range was 3.8-18.4 mg/dl. The results showed that the TcB index correlates well with the serum bilirubin measurement: the regression analysis was: r = 0.878, y = 10.78 + 0.909 x, P less than 0.001. However, the regression line showed that at a serum bilirubin level above 12.9 mg/dl the sensitivity of the TcB was 69% and the specificity 92%, while its positive and negative predictive values were 58% and 95% respectively. There was a fair amount of variability around the regression line which may lead to significant errors in clinical decision-making. Thus, the TcB at present has grave limitations which restrict its usefulness in the newborn.     

Micro-invasive management of neonatal bilirubinemia.

The present study aims at analyzing the suitability of transcutaneous approach and filter paper technique using Minolta Jaundicemeter in the management of neonatal bilirubinemia. I compared serially measured values of Serum Bilirubin Index (SBI) by using filter paper technique and transcutaneous bilirubin index (TcBI) with serum bilirubin level determined by Diazo Method in 100 clinically jaundiced newborns and in 25 neonates at birth. The estimation of TcBI is simple, quick, reliable and non-traumatic to the newborn with no workload on the laboratory and technician. However, different nomograms are to be prepared for different laboratories, as also for the newborns with difference in skin pigmentation, gestational age and after phototherapy. SBI determined by filter paper technique eliminates these limitations. Moreover, the linear correlation was stronger between SBI and Diazo values (r = 0.9343, p < 0.001) in comparison to TcBI with Diazo values (r = 0.9090, p < 0.001). Further SBI readings almost correspond with actual serum bilirubin levels while corresponding TcBI values were much higher especially at higher diazo values. Thus TcBI can be used routinely for the surveillance of neonatal jaundice till it reaches a level corresponding to critical serum bilirubin level at which active management is required. At this point, serum bilirubin level may be confirmed by SBI.     

Evaluation of a new transcutaneous bilirubinometer in Chinese newborns

OBJECTIVE: To evaluate the use of a new transcutaneous bilirubinometer (JM-103 Minolta Airshields) for detection of hyperbilirubinaemia in term or near-term healthy Chinese newborns. METHODS: Transcutaneous bilirubin (TcB) was used to screen for severe hyperbilirubinaemia in newborn infants. Blood was taken for total serum bilirubin (TSB) measurement if the initial TcB level was higher than the 40th centile in Bhutani's nomogram. Paired TcB and TSB results were then reviewed over 6 months. The correlation as well as the mean difference between the two methods were calculated. The clinical application of TcB with Bhutani's nomogram in the prediction of severe hyperbilirubinaemia in low-risk, medium-risk and high-risk thresholds for phototherapy was also analysed. RESULTS: 997 paired TcB and TSB measurements were evaluated in term or near-term newborns. TcB was significantly correlated with TSB, with a correlation coefficient of 0.83 (p<0.001). Their mean difference was 21.7 micromol/l (SD 21.2, p<0.001), with the 95% limits of agreement between -19.9 and 63.3 micromol/l. In both low-risk and medium-risk thresholds for phototherapy, using the 75th centile of Bhutani's nomogram as threshold, TcB could identify all cases and had a sensitivity and negative predictive value of 100% each, a specificity of 56% and positive predictive value of 23%. For high-risk cases, using the 75th centile as cut-off, the sensitivity and negative predictive value were reduced to 86.7% and 97.0%, respectively. CONCLUSION: An accurate point-of-care bilirubin analyser facilitates bilirubin screening and avoids unnecessary blood tests. Although using the transcutaneous bilirubinometer JM-103 might result in a significant difference between TcB and TSB measured in Chinese newborns, combining the use of TcB and the 75th centile in Bhutani's nomogram as the cut-off level can identify all cases of significant hyperbilirubinaemia.     

Transcutaneous bilirubinometry: serum bilirubin measurement using transcutaneous bilirubinometer (TcB). A preliminary study

While the transcutaneous bilirubinometer (TcB) was originally developed for use as a jaundice meter, we have shown that it can also be used as a bedside instrument for direct measurement of serum bilirubin. An analysis of 130 samples indicates that total serum bilirubin measurement using the TcB is simple and accurate. A comparison with the AO bilirubinometer showed a highly significant coefficient or correlation (r = 0.99) for total serum bilirubin concentration. The addition of hemolysates caused no effect on TcB reading obtained by the TcB instrument, even at levels above those usually encountered in sera of newborn infants. The AO cuvette is very suitable for use in this measurement, since this method requires less than 15 microliters of serum. One of the disadvantages of this method may be that it yields somewhat lower (5%) than actual serum bilirubin concentrations in the range above 20 mg/dl, and somewhat higher (20%) than actual serum bilirubin concentrations in the range below 10 mg/dl. Our study demonstrated the TcB instrument to be a useful device for bedside determination of serum bilirubin in the screening of neonatal hyperbilirubinemia. However, though useful as a screening test, it does not provide such an accurate determination of serum bilirubin concentration as the AO bilirubinometer.     

Transcutaneous Bilirubinometry: Effect of Postnatal Age

The purpose of this study was to determine whether the postnatal age might affect the accuracy and reliability of transcutaneous bilirubin measurements. A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breastfed newborn infants during the first 12 days of life. We divided them into three groups according to postnatal age and studied the effect of postnatal age on the accuracy and reliability of TcB measurements. Our study revealed that the most reliable site for transcutaneous bilirubin measurements changed from the forehead to the sternum with advancing postnatal age (i.e. forehead for0–3 days, chest for4–5 days, sternum for 6 days and later).