Abstract
Serum testosterone measurements have utility in diagnosis of clinical conditions characterized by both increased and decreased testosterone concentrations
. Studies have indicated that testosterone immunoassays may give inaccurate results for women and children. We evaluated the performance of a second generation testosterone immunoassay from Roche Diagnostics.
Testo II performed on a Modular
Analytics E 170 analyzer is an automated random access electrochemiluminometric assay. We evaluated limit of blank (LoB), imprecision, linearity, interference, and method comparison with liquid chromatography-tandem mass spectrometry assay (LC-MS/MS). Method comparison included the current generation Roche testosterone assay (Testo I) and the Access 2 testosterone chemiluminometric assay (Beckman Coulter). Results for men and women were analyzed for analytic concordance. The relative % differences of immunoassay compared to LC-MS/MS results were evaluated.
The LoB was 0.07
nmol/l. Total imprecision was <
6%. The assay was linear from 0.2 to 46.6
nmol/l. Negative interference was observed for lipemia at concentrations >
22.5
g/l. Analytic concordance showed improved specificity for women. Comparison of results to LC-MS/MS indicated comparable performance with other immunoassays for men and improved performance for women, boys, and girls with mean differences of 0.5%, −
0.7%, and 24.4%, respectively.
The Roche Testo II assay demonstrated excellent precision. Comparison to 2 other automated immunoassays showed comparable performance for men and improved performance for women and children. However, challenges still exist for quantifying testosterone concentrations <
10.4
nmol/l for men and <
1.7
nmol/l for women and children by immunoassay.