Evaluation of Total Bilirubin Determination in Neonatal Whole-Blood Samples by Multiwavelength Photometry on the Roche OMNI S Point-of-Care Analyzer

Jaundice is a common finding in healthy and diseased neonates. Because of early discharge, the risk of kernicterus is a re-emerging problem in the United States. Precise and accurate determination of plasma total bilirubin concentrations is the indispensable prerequisite for proper management of jaundiced infants. In this multicenter study, we investigated the analytical performance of the Roche OMNI S blood gas analyzer for measurement of total bilirubin from neonatal whole blood using a multiple-wavelength photometric method. The results were evaluated relative to simultaneously obtained results from routine clinical chemistry methods and one other point-of-care testing device. A total of 496 heparinized blood samples were drawn from newborns (≤39 days of age). An aliquot of the whole-blood sample was measured on Roche OMNI S and on the Radiometer ABL 735. Plasma was prepared from the remaining sample for laboratory analysis. Total bilirubin was measured on the LX20 (Beckman Coulter), Hitachi 912 and 717 (Roche Diagnostics), Dimension (Dade Behring), and Vitros 250 (Ortho Clinical Diagnostics). Plasma bilirubin concentrations covered the diagnostic relevant range up to 23.7 mg/dL. Overall, there was a good agreement between the bilirubin concentrations measured in whole blood on Roche OMNI S and Radiometer ABL 735 and between the comparison routine analyzers. Correlation coefficients were all above 0.94, and the slope of the regression lines ranged from 0.971 to 1.172. The mean biases ranged from -0.3 to 1.4 mg/dL, and the differences between comparison methods were less than those reported in proficiency testing. Direct spectrophotometric measurement of bilirubin in neonatal whole-blood samples gives results that compare well with those obtained using routine clinical chemistry methods. Its advantages are the very small volume of blood and the short turn-around time. Thus, the Roche OMNI S analyzer represents a suitable method for monitoring neonatal jaundice at the point of care.