Interferences of o-raffinose cross-linked hemoglobin in three methods for serum creatinine

The interferences of o-raffinose cross-linked hemoglobin (Hemolink(TM)) were examined and compared in two serum creatinine methods on the Hitachi 717 [Boehringer Mannheim (BMC) and Synermed] and in an enzymatic creatinine method on the Vitros 750 (Johnson & Johnson). Interference was considered significant when the change in creatinine concentration from the control exceeded the 95% confidence limits of each method. Significant interference was observed for the BMC/Hitachi 717 method with Hemolink greater than or equal to 5 g/L. No interference was observed for the Synermed/Hitachi 717 assay with Hemolink up to 30 g/L in normal samples and up to 50 g/L in samples with increased creatinine. No interference was observed for the Vitros 750 assay with Hemolink up to 50 g/L at both normal and increased concentrations of creatinine. Although the BMC/Hitachi 717 method was considered unacceptable, the Synermed/Hitachi 717 and the Vitros 750 methods allow accurate quantification of serum creatinine in the presence of Hemolink.