The presence of interfering species in assays confounds the interpretation and can lead to poor patient outcomes. In clinical chemistry interference in an assay can have multiple causes and may be specimen (patient) specific or more broadly identified in a wide range of patients [1]. If newly developed assays are likely to suffer from the most common interferents such as hemolysis, lipemia, or icterus, then this is assessed during the assay validation process. Immunoassays are prone to interference because of the complex nature of the interaction between the analyte and the detecting antibody. Interference can occur because of the non-specificity of the antibody-antigen reaction, problems with other binding proteins, or quenching of the signal process [2]. Often the potential interferent is suggested by differences in results from different assays for a particular analyte, but with different specificities [3], interactions between serum proteins and specific assay components, or non-specific heterophilic antibodies.