Comparability of Total Bilirubin methods for neonatal samples across 6 NHS trusts within North West England

BACKGROUND: The National Institute for Health and Care Excellence (NICE) guideline: management of neonatal jaundice [CG98] outlines total bilirubin (TBil) thresholds for the treatment of neonatal jaundice. Despite wide analytical variation in TBil, evidenced on external quality assessment schemes, the thresholds are based on a single Roche diazo assay. Adoption of these thresholds may result in inappropriate treatment decisions depending on the analytical methodology. This study assesses TBil method bias using pooled neonatal (<29 days) samples, prompted by incidents within Greater Manchester where differences in neonatal TBil measurements obtained due to transfer of care across sites caused clinical confusion. METHODS: Seventeen serum and 9 plasma neonatal pools were analysed in duplicate on 6 platforms: Roche Cobas 701, Roche Pro, Abbott Alinity, Beckman Coulter AU5800, Siemens Atellica and Siemens XPT , utilising 5 diazo and 2 vanadate oxidation methodologies. Measurement biases compared to Roche Cobas were assessed. RESULTS: Siemens Atellica and XPT vanadate oxidation methods exhibited significant positive bias: 17.4% [95% CI: 15.0-19.8%] and 17.0% [95% CI: 15.0-19.0%], respectively. All diazo methods were within desirable bias limits (+/-8%) as defined by the European Federation of Clinical Chemistry and Laboratory Medicine analytical performance specifications. Bias for Siemens vanadate oxidation and Beckman Coulter diazo methods exhibited matrix variation. CONCLUSIONS: Use of Siemens TBil vanadate oxidation method may lead to over treatment of neonatal jaundice when using NICE [CG98] thresholds. Laboratory professionals should evaluate the appropriateness of their TBil methodology in collaboration with their neonatal teams to minimise risks of overtreatment.