Journal of Clinical Neonatology

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 7  |  Issue : 4  |  Page : 198--201

The accuracy of repeated use of BiliCal for transcutaneous bilirubin measurement in term newborns using BiliCheck device


Saad Abdullah Alsaedi 
 Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia

Correspondence Address:
Dr. Saad Abdullah Alsaedi
Faculty of Medicine, King Abdulaziz University, Jeddah
Saudi Arabia

Abstract

Background: Transcutaneous bilirubin (TcB) measurement provides an accurate estimate of total serum bilirubin (TSB) values in healthy term infants. TcB measurement is quick, simple, and less invasive. BiliCheck is a device which is validated to measure TcB using a disposable single use probe to calibrate the device. The aim of this prospective observational study is to evaluate the accuracy of BiliCheck device for measurement of TcB when BiliCal is reused twice and three times in the same newborn. Methods: Healthy jaundiced term newborns required TSB measurement more than once were included in the study. BiliCheck was used to measure TcB within 10 minutes of TSB measurement using the same Bilical up to 3 measurements for the same newborn. Pearson correlation of each TSB and TcBpair as well as the Bland-Altman analyses was used to assess the level of the first, second and third TSB and TcB pair's variability. Results: TcB was measured twice using the same BiliCal in 225 newborns and three times in 95 newborns. Mean TSB was 149.5 ± 44.3, 177 ± 44.6, 192.6 ± 39.3 umol/l and mean TcB was 159 ± 46.5, 183 ± 47.7, 186.5 ± 40 umol/l when TSB and TcB were measured for the 1st, 2nd and 3rd time respectively. There was a significant correlation between TSB and TcB when BiliCal was used for 1st, 2nd and 3rd time (r = 0.83, 0.82, 0.71 respectively). The mean difference of (TcB – TSB) was 9.8 ± 26.9, 5.2 ± 29.2, -0.3 ±1.8 umol respectively. Conclusion: TcB level measured by BiliCheck has an excellent correlation with TSB not only when the disposable probe, BiliCal, is used for the first time but also when it is reused for the second and third time.



How to cite this article:
Alsaedi SA. The accuracy of repeated use of BiliCal for transcutaneous bilirubin measurement in term newborns using BiliCheck device.J Clin Neonatol 2018;7:198-201


How to cite this URL:
Alsaedi SA. The accuracy of repeated use of BiliCal for transcutaneous bilirubin measurement in term newborns using BiliCheck device. J Clin Neonatol [serial online] 2018 [cited 2019 Mar 19 ];7:198-201
Available from: http://www.jcnonweb.com/text.asp?2018/7/4/198/243345


Full Text



 Introduction



Jaundice is a common diagnosis during the neonatal period. Treatment is conservative most of the time; however, high bilirubin levels need treatment by phototherapy and or exchange transfusion to prevent bilirubin-induced neurologic dysfunction.[1],[2]

Chemical methods for measurement of bilirubin in the sera of newborn infants are the standard of care in the assessment of neonatal jaundice. However, blood sampling from heel prick or from veins involves discomfort and pain for newborns. In addition, it requires the withdrawal of more blood from those small infants. Over the last 20 years, several studies documented the value of transcutaneous bilirubin (TcB) measurement in newborns.[3],[4],[5] Transcutaneous bilirubin measurement is quick, simple, and less invasive.

It provides an accurate estimate of TSB values in healthy term infants and it can be used as a screening method before the discharge newborns from the nursery.[3],[4],[5]

BiliCheck® (SpectRx, Norcross, GA, USA) is one of the devices, which is widely used and validated for TcB measurement in newborns. It corrects for the skin's melanin, gestational age (GA), and the skin's hemoglobin content. It requires calibration before each measurement using a disposable probe (BiliCal, SpectRx, Norcross, GA, USA). Each single use, disposable BiliCal costs 8.0–10.0 US dollars, which adds to the cost of TcB measurement. The aim of this prospective cohort study is to evaluate the accuracy of BiliCheck device for the measurement of TcB when BiliCal is used twice and three times for the calibration of the device in the same term newborn.

 Methods



This was a prospective, cohort study of jaundiced, healthy term infants who were admitted during the study at the Newborn Nursery at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia, from September 2015 to July 2016. KAUH is a tertiary care academic center with 4000 deliveries per year. Full-term newborns ([GA], 37–42 weeks) who fulfilled the following criteria were included in this study: clinically jaundiced but otherwise healthy; postnatal age ≤168 h; decision by the treating physician to measure TSB for clinical purposes; and parental consent to participate in the study. The exclusion criteria were newborns requiring phototherapy or exchange transfusion, newborns with skin bruises, or hemangioma on the forehead or had major congenital malformation, sepsis, congenital viral infections or conjugated jaundice. The study was approved by the Ethics Committee of the Faculty of Medicine and KAUH, Jeddah, and was conducted according to the principles of Helsinki Declaration. Once the treating physician decided to measure TSB and the parents provided the consent, the newborn was enrolled in the study. Transcutaneous bilirubin was measured by five trained nursery nurses. All TcB measurements were obtained from the forehead using the same BiliCheck device. The BiliCheck was calibrated before each measurement using a disposable probe (BiliCal, SpectRx, Norcross, GA, USA) as per the manufacturer's instructions.[6] Areas with hair, hyperpigmentation, bruises, and hemangioma on the forehead were avoided. The device displays the average of five measurements from a different area of the forehead in μmol/L for each bilirubin value. For each infant, the same BiliCal is kept in the bedside to be reused for further TcB measurement up to three times in case he/she requires further TSB measurement. Only infants who had 2–3 TcB measurements were included in the analysis. All blood specimens were obtained by heel sticks within 10 min after TcB measurements. After warming of the heel and lancet puncture, blood was collected by drip method into heparin-containing tubes. Diazo method (Dimension Vist. System and Flex Reagent cartridge, Siemens) was used to measure TSB.[7] The following demographic data were recorded for all infants enrolled in the study: GA; gender; birth weight; mode of delivery; and postnatal age in hours at the time of TSB and TcB measurements.

Statistical analysis

The Statistical Package for the Social Sciences version 21 (IBM Inc., Armonk, NY, USA) was used for statistical analysis. The agreement between the measurements of first, second, and third TSB and TcB pairs was assessed using Pearson's correlation and linear regression model including 95% confidence interval. Since Pearson's coefficient alone can be a poor indicator to estimate the agreement between two diagnostic tests, the Bland–Altman analysis was used to assess the level of the first, second, and third TSB and TcB pair's variability.[8] In this analysis, the mean bias of each TSB-TcB measurement was compared against their mean for every patient, and variability was defined as ±1.96 standard deviation (SD) of the mean bias.

 Results



The TcB was measured twice using the same BiliCal in 225 newborns (TcB1and TcB2). The same BiliCal was used to measure TcB for the third time (TcB3) in 95 out of 225 newborns. The mean GA ± SD was 38.8 ± 1.2 weeks (range; 37–42 weeks), the mean birth weight was 3.2 ± 0.5 kg (range: 1.7–4.8 kg), 110 newborns (49%) were male, and 160 newborns (71%) were born by spontaneous vaginal delivery. The mean age when BiliCal was used to measure TcB for the first time (TcB1) was 39.2 ± 17.4 (range: 9–120) hours. The mean age when the same BiliCal was used to measure TcB for the second time (TcB2) was 57.7 ± 20.2 (range: 20–131) h. The mean age when the same BiliCal was used to measure TcB for the third time (TcB3) was 71.3 ± 23.2 (range: 27–164) h. Total serum bilirubin and TcB, mean of TSB + TcB, and mean difference (TcB-TSB) when BiliCal was used for the first, second, and third time to measure TcB are shown in [Table 1]. Pearson's correlation, the mean, and the mean of the difference of TSB and TcB pair when BiliCal was used for first, second, and third time are shown in [Figure 1], [Figure 2], [Figure 3].{Table 1}{Figure 1}{Figure 2}{Figure 3}

 Discussion



According to the manufacturer recommendation, a disposable BiliCal should be used to measure TcB to calibrate the device before each use. However, each disposable BiliCal costs 8–10 US dollar which adds to the cost of the test. If the reuse of BiliCal to measure TcB in the same newborn is reliable and accurate, it will reduce the cost of TcB measurement.

In our study, linear regression analysis revealed that there is a statistically significant correlation between TSB and TcB when the BiliCal is used to measure TcB for the first time (r = 0.83, mean difference = 9.8 ± 26.9 μmol/L). This in agreement with other studies which reported a significant correlation, r = 79–84.[3],[6],[9]

We found that there was also statistically significant correlation between TSB and TcB when BiliCal was used to measure TcB for the second and third time in the same newborns, r = 0.82 and r = 0.72, respectively. However, the correlation decreases when BiliCal was reused for the third time. BiliCal overestimates TSB when used to measure TcB for the first and second time.

However, it underestimates TSB When it is reused for the third time [Table 1]. Based on this study, in limited resources circumstances, the BiliCal can be used up to 3 times in the same newborn to reduce the cost. To the best of our knowledge, this is the first study evaluated the accuracy of TcB measurement using the disposable BiliCal more than once. More studies are needed to confirm our finding in this study. The limitations of our study include the relatively small number of newborns who had measurement of TcB for the third time and the fact that TcB measurements were performed by more than one nurse rather than one nurse. This will raise the issue of interobserver variability. However, in practice, more than one nurse measures TcB.

In conclusion, TcB level has excellent correlation with TSB not only when the disposable probe, BiliCal, is used for the first time but also when it is reused for the second and third time. It is expected that this will reduce the cost of TcB measurement by BiliCheck device.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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