"Matrix effects" in immunoassays.

This article deals with "matrix effects" in immunoassay systems. As each component has its own matrix (buffer, antibody, separation agents), the term matrix effect--usually only referring to the matrix of the sample--has been replaced by the term interference effect. The possible sites of interference have been dealt with in turn, taking each component/step of an immunoassay separately. Results of assay improvement due to the removal of "matrix effects" are given using the PTH-assay as example. The change in results due to tampering with the serum matrix is given using the determination of free thyroxine in commercial quality control sera.