New insights into the diagnostic accuracy of complexed and total prostate specific antigen using discordance analysis characteristics.

Purpose: Comparison of diagnostic performances of total and complexed prostate specific antigen (tPSA, cPSA) using ROC curve analysis resulted in controversial interpretations. To overcome the biases due to analysis of subgroups selected by concentration ranges of only 1 marker the novel approach named discordance analysis characteristics is presented.

Materials And Methods: DAC method includes only patients who are discordantly categorized by the tests under investigation using cutoffs with identical sensitivity.

Discordance analysis characteristics as a new method to compare the diagnostic accuracy of tests: example of complexed versus total prostate-specific antigen.

Background: ROC curve analysis is used to compare the overall diagnostic accuracy of tests, but its application to subgroups selected by a concentration range of only one marker may show severe biases. We developed a new approach, which we have named discordance analysis characteristics (DAC).

Methods: The DAC method is based on a generalization of the McNemar test so that for a given pair of cutoff values only those patients are analyzed who are categorized differently by the two tests compared.

Continuous age-dependent reference ranges for thyroid hormones in neonates, infants, children and adolescents established using the ADVIA Centaur Analyzer.

In neonates, infants, children and adolescents serum concentrations of the thyroid hormones show a clear age dependency. Currently, age-dependent thyroid hormone reference ranges for the new ADVIA Centaur immunoanalyzer are not available. Thyroid-stimulating hormone (TSH), free thyroxine (FT4), total thyroxine (T4), free triiodothyronine (FT3) and total triiodothyronine (T3) were determined in the sera of 460 healthy children aged 0 daysto 18 years from an inland (n=308) and a seaside city (n=152) using the Bayer ADVIA Centaur analyzer.