The clinical impact of implementing the Roche® bilirubin total Gen.3 method on neonate phototherapy.

To predict the impact of implementing the Roche® Gen.3 bilirubin total method on the number of bilirubin results that would trigger phototherapy using the phototherapy nomogram published in the Canadian Paediatric Society (CPS) Guidelines for Treatment of Hyperbilirubinemia. BILTS method results (N=563) were obtained on the Roche® C501 analyzer and the corresponding Bilirubin Total Gen.3 assay results were derived by linear regression. Total bilirubin results, gestational age and postnatal age were plotted with the CPS phototherapy nomogram to determine if phototherapy was indicated with both the BILTS and Gen.3 methods. Clinical thresholds for phototherapy using the BILTS and new Gen.3 methods were compared by Pearson's chi square test. 284 bilirubin results obtained from infants 35-37 weeks gestation (n=157 neonates) and 279 results from term infants >38 weeks gestation (n=224 neonates) were interpreted with the CPS phototherapy nomogram as either with or without risk factors. Use of the Gen.3 assay reduced the number of bilirubin results that would meet the high-risk threshold line to initiate phototherapy by 7% (p≤0.05) for 35-37 week gestation infants and would reduce phototherapy by 6% (p≤0.05) for >38 week gestation infants with the medium-risk threshold line compared to when the BILTS method was used. Replacement of the BILTS method by the Gen.3 bilirubin method is anticipated to be associated with a 7% decrease in the number of neonate results that would meet phototherapy thresholds. It cannot be determined if the BILTS assay was associated with a 7% over-treatment or the Gen.3 assay will be associated with 7% under-treatment. While standardization of bilirubin assays remains elusive, nomograms based on bilirubin methods will remain susceptible to method-biases and patient care decisions will remain subject to this uncertainty.