PHILOSOPHY OF MEASUREMENT BY MEANS OF IMMUNOASSAYS

Starting from the explanation of the terms "comparison" and "quantification" a concept of a metrologically correct measuring system is derived. The paper discusses how this concept can be applied to immunoassays. The investigation led to the following conclusions: 1. Immunoassays are not principally either comparative tests or quantitative tests. Whether or not a correct measuring system can be construed for an immunoassay test depends on the intended use and the conditions in the specific individual case. 2. If certain requirements, which are discussed in detail, are fulfilled, immunoassays can be used for measuring the substance composition of biological materials. Critical points are the unambiguous definition of the "chemical entity" of the analyte to be determined (especially of macromolecules), the calibration of the measuring system by means of standards, and the problem of matrix effects.