Neonatal total bilirubin measurements: Still room for harmonization

Background: Universal screening of total bilirubin in neonates is endorsed by experts from the American Academy of Pediatrics and is increasingly common. Methodological differences between diazo-based quantitation (wet chemistry) and reflectance spectrophotometric quantitation (dry chemistry) can lead to unnecessary treatment. A recent recalibration of the only commercially available dry chemistry assay was issued to reduce these differences. This study evaluated the post-recalibration bias between the two assay types. Methods: Method comparison of neonatal total bilirubin (Beckman AU680 vs Ortho-Clinical-Diagnostics Vitros) was achieved using freshly-drawn neonatal samples (n = 239). Results: The Vitros produced neonatal bilirubin results with a 12.4% average positive bias compared to the AU680 total bilirubin results. The AU680 direct bilirubin reaction had 5.6% cross reactivity with unconjugated bilirubin. Conclusions: Neonatal or total bilirubin quantitation remains unharmonized between platforms. Care should be taken to understand the bias of specific platforms. (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.