The accuracy of transcutaneous bilirubin to identify hyperbilirubinemia in jaundiced neonates

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.

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.

Can serum albumin level affect the transcutaneous bilirubinometry in term neonates?

BACKGROUND

Jaundice is the quite common benign condition in neonates, but due to its potential toxicity, neonates must be monitored. This study was aimed to evaluate the effect of serum albumin level on the transcutaneous bilirubin (TcB) measurements in term neonates with unconjugated hyperbilirubinemia.

METHODS

Serum albumin and total serum bilirubin (TSB) of 252 jaundiced term neonates were estimated and simultaneously TcB was measured over sternum and the effect of serum albumin on TcB measurements was evaluated.

RESULTS

The correlation between TSB and TcB was linear and significant for the entire cohort. When this correlation was studied separately in the groups with different albumin levels, maximum correlation (r = 0.888, R2 linear = 0.789, p < 0.001) was observed in group 1 with hypo-albuminemia followed by in group 2 with normal albumin levels (r = 0.854, R2 linear = 0.729, p < 0.001) and group 3 with higher albumin levels (r = 0.809, R2 linear = 0.689, p < 0.001). Bland-Altman plot analysis of whole study population demonstrate good agreement between TSB and TcB [95% CI = -0.038 to 0.493 mg/dL, 17/252 = 6.75% outside the limits of agreement, Mean difference = 0.227]. This analysis in different groups also show good agreement between TSB and TcB.

CONCLUSIONS

The correlation between the TSB and TcB may affected by serum albumin level. Therefore, transcutaneous bilirubinometry is not able to replace invasive TSB measurement. However, in the absence of TSB it could be an alternative to measure the level of bilirubin in term neonates.