Current concepts in standardization of cardiac marker immunoassays.

Cardiac markers are measured by a number of different immunoassays using specific antibodies directed to the respective antigens. Lacking assay standardization, different results from different assays measuring the same marker may be obtained and this problem may cloud interpretations of reported data. Presently, there are no reference procedures for cardiac markers; certified reference materials should still be established and, at least for cardiac troponins, the analyte in the patients' blood is significantly different from newly synthesized protein. It is therefore clear that the problems of cardiac marker standardization will not be quickly solved. A number of projects are, however, underway under the auspices of the IFCC and other organizations. The aim of this opinion is to reflect on some concepts related to the implementation of a metrologically correct measurement system, giving practical examples on how these concepts can be applied to immunoassays measuring cardiac markers.