What is the Origin of Immunoassay Interference?

The concept is rooted in clinical chemistry and laboratory diagnostics, arising from the inherent vulnerability of antibody-based assays to cross-reactivity and non-specific binding. The increasing use of high-sensitivity immunoassays has amplified the clinical significance of these interferences.

What is the Mechanism of Immunoassay Interference?

Common mechanisms of interference include the presence of heterophile antibodies, which bridge the capture and detection antibodies of the assay, causing a false positive signal, or the presence of high concentrations of certain drugs or autoantibodies that block the binding site, causing a false negative. For hormone testing, unexpected clinical results that contradict the patient's presentation should prompt the clinician to investigate potential assay interference, often requiring confirmation with a different analytical method, such as mass spectrometry.

Immunoassay Interference

Meaning

Immunoassay Interference describes a phenomenon where non-target substances present in a patient’s biological sample disrupt the specific binding reaction between the assay’s reagents and the target analyte, leading to inaccurate, often misleading, quantitative results. This interference can result in falsely elevated or falsely suppressed measurements of hormones, such as thyroid hormones or sex steroids, profoundly complicating clinical diagnosis and management. Recognizing and mitigating immunoassay interference is a critical aspect of laboratory medicine.