Reference values and methods comparison of a new testosterone assay on the AxSYM system

Objectives: We have contributed to the Design Validation Protocol of the new Abbott AxSYM Testosterone assay with a study on reference values and methods comparison. Design and methods: For reference values a population of 45 women and 30 men was tested. In methods comparison, 132 samples for the AxSYM vs. ACS-180, and 30 for the AxSYM vs. Elecsys were used. Pearson and intraclass concordance coefficients and Passing-Bablock test were performed for overall group, men and women. Results: Reference values were 0.9–3.1 (females) and 1.0–30.2 nmol/L (males). Globally, a good agreement between methods in both the AxSYM vs. ACS-180 (slope: 0.88, y-intercept: 0.67, r = 0.961) and the AxSYM vs. Elecsys (slope: 1.08, y-intercept: 0.31, r = 0.935) studies was found. Slightly worse results were observed for women. Conclusions: The reference range of testosterone by the AxSYM system matches with those published for other methods. An acceptable agreement between the AxSYM Testosterone assay and both a classical (ACS-180) and a more recent (Elecsys) methodology was observed.