Interference from endogenous antibodies in automated immunoassays: what laboratorians need to know

Full automation of laboratory procedures confers numerous advantages over semi-automated/manual tests because equipment, reagents and the computation of results are offered as an integrated package. Automation has allowed millions of immunoassay tests to be performed with good sensitivity and excellent precision but inaccuracy caused by interference from endogenous immunoglobulins/antibodies remained a problem (irrespective of the immunoassay's format). Interference leading to a falsely high or low result affects a specific sample and may not be obvious despite the strictest laboratory control schemes. Reporting and interpreting such potentially erroneous data remained however the responsibility of the clinical laboratory despite the limited information supplied by their providers. The focus of this review is on highlighting the potential downside of current disjointed and blurred arrangement between the developers/providers of immunoassays, and the laboratorians responsible for providing these data to their clinical colleagues. These limitations can be addressed by drawing attention to the importance of the key fundamentals underpinning these immunologically based analyses which, if carefully considered, could help to formulate pragmatic strategies to reduce errors in immunoassays. In this review, the inherent fallibility of the binding reaction between an antigen and antibody will be reiterated. The difficulties in defining reaction rate kinetics in non-equilibrium automated assays, the potential clinical error rate and the need for minimising analytical error rate of these automated technologies will be highlighted.