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Transcutaneous Bilirubinometry in Jaundiced Newborns

Three Part Question

In [term and near term newborn infants] is [transcutaneous bilirubinometry when compared with serum bilirubin estimation] accurately [identify all cases of significant jaundice (i.e. .250 mmol/l)?]

Clinical Scenario

While doing a discharge check on a 3 day old baby, a paediatric SHO notices mild jaundice and prepares to perform a serum bilirubin estimation (SBR). She explains this to the mother, who breaks into tears and asks the SHO if there was any way she could check the level of jaundice without doing a blood test. The SHO discusses this with the neonatal consultant who mentions "We used to have a transcutaneous bilirubinometer when I was an SHO, but we stopped using it because it was inaccurate".
A more sympathetic registrar gives you a recent review article (Ip) on jaundice which indicates that the older generation bilirubinometers were shown to be inaccurate for clinical use; however, a newer version, the "SpectRx Bilicheck" may be more reliable. Bilicheck (BC) uses multiple wavelengths of light, and the manufacturer claims that the monitor is unaffected by skin pigmentation and other interfering factors.
You wonder if the Bilicheck could be safely used as a screening test for jaundice on the postnatal wards.

Search Strategy

We searched PubMed under clinical queries and diagnosis
Using keyword ''Bilicheck''

Search Outcome

Which identified three studies, all of which were of good quality.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Bhutani et al,
2000
490 term and near term (>35 weeks, >2 kg) up to 4 days Gold standard = high performance liquid chromatography (HPLC)Prospective CohortSensitivity and specificity on comparison with gold std Hour specific centile chart usedFor picking up SBR >256 Ámol/l (95th centile) Sensitivity 100%, Specificity 88% All babies with SBR <40th centile had BC <40th centileOnly 3.1% had SBR >256 Ámol/l Bilicheck was as accurate as standard laboratory measurement No babies with significant jaundice would be missed All newborns at discharge had SBR check irrespective of clinical jaundice
Rubaltelli et al,
2001
Newborns >30 weeks and <28 days, 210 infants in 6 European hospitals recruited. HPLC as gold standardProspective cohortSensitivity and specificity on comparison with gold stdAt HPLC cut off 222 Ámol/l, BC had a sensitivity and specificity of 93% and 73% and while standard lab method had sensitivity and specificity of 95% and 76% At HPLC of 290 Ámol/l BC and standard lab method had sensitivity and specificity of 90%/87% and 87%/83%BC more accurate than standard lab SBR, especially at higher values Independent of race, gestation, and weight
Samanta et al,
2004
300 term and near term newborn babies Standard laboratory methodProspective cohortSensitivity and specificity on comparison with gold std91% sensitivity and 66% specificity in diagnosing significant jaundice (i.e. >250 Ámol/l)55% reduction in blood sampling would have occurred if Bilicheck was used as a screening tool 5 babies with significant jaundice (>250 Ámol/l) were missed. But all the 5 had SBR <300 Ámol/l)

Comment(s)

We intended to use transcutaneous assessment on the postnatal ward as a screening test. It was important that the Bilicheck would not miss any significant jaundice. We arbitrarily chose 250 Ámol/l (a level below which an intervention would be unlikely in term or near term babies after 24 hours). We wanted to determine if Bilicheck had a high sensitivity at this SBR level, so that babies would not need a blood test if Bilicheck value was less than 250 Ámol/l. Bilirubin values were converted to SI units (Ámol/l) (1 mg = 17.1 Ámol/l) for easiness of comparison. The review is confined to three good quality studies identified following a basic PubMed search. The first two studies compared Bilicheck with the internationally accepted gold standard for bilirubin estimation2ľ4 (that is, high performance liquid chromatography) and found that it was at least as good as laboratory method. Even though all studies showed good correlation between the Bilicheck readings and laboratory values, it was more important to establish that no cases of significant jaundice would be missed when it is used as a screening test. Considering bilirubin levels of >250 Ámol/l as significant jaundice, it appears that Bilicheck can be used to exclude significant jaundice and therefore reduce the number of serum bilirubin estimations. It is unlikely that the sensitivity of Bilicheck would be 100% in clinical practice; however, by using a low cut off for estimating serum bilirubin, the false negatives would be still well below the levels associated with neurotoxicity. Bilicheck has been shown to have similar efficacy in a wide range of ethnic groups. Since we wanted to examine the use of Bilicheck in postnatal wards, this review is confined to only term and near term babies. There are insufficient data to support the routine use of Bilicheck on babies receiving phototherapy at present.

Clinical Bottom Line

In healthy term and near term newborn babies, ''Bilicheck'' can be safely used as a screening test for jaundice to avoid blood sampling.

References

  1. Ip S, Chung M, Kulig J, et al. American Academy of Pediatrics Subcommittee onHyperbilirubinemia. An evidence-based review of important issues concerning neonatal hyperbilirubinemia. Pediatrics 2004;114:130ľ53.
  2. Bhutani VK, Gourley GR, Adler S, et al. Noninvasive measurement of total serum bilirubin in a multiracial predischarge newborn population to assess the risk of severe hyperbilirubinemia. Pediatrics 2000;106:17.
  3. Rubaltelli FF, Gourley GR. Loskamp N. et al. Transcutaneous bilirubin measurement: a multicenter evaluation of a new device. Pediatrics 2001;107:1264ľ71.
  4. Samanta S, Tan M, Kissack C. et al. The value of Bilicheck as a screening tool for neonatal jaundice in term and near-term babies. Acta Paediatr 2004;93:1486ľ90.