Endocrine Abstracts

Background: Androstenedione (ASD) levels are used to assess androgen production, adrenal gland and ovarian/testicular function, and diagnosis/monitoring of patients with hyperandrogenism from suspected cortisol-related enzyme deficiencies. According to international diagnostic guidelines, ASD can confirm biochemical hyperandrogenism in suspected polycystic ovary syndrome (PCOS) when total/free testosterone are not elevated. The Elecsys ASD assay (Roche Diagnostics) is a competitive electrochemiluminescence immunoassay for in-vitro quantitative determination of ASD in human serum/plasma. We evaluated the performance of this new, automated assay versus an ASD isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) candidate reference method, and determined reference ranges in different clinical cohorts.

Methods: Elecsys ASD assay performance (cobas e 602/cobas e 801 analysers) was evaluated at three sites in Germany/Spain; method comparison was performed internally by Roche Diagnostics; reference ranges were determined at two sites in Germany. Repeatability and intermediate precision were assessed according to CLSI EP05-A3, using three control levels and five human serum pools (n = 75 each) covering the assay measuring range (0.15–10.00 ng/ml); one run per day for 5 days. Method comparisons versus commercially available immunoassays (IMMULITE ASD [Siemens] and LIAISON ASD [DiaSorin]) and an ID-LC-MS/MS candidate reference method were conducted using 421 serum samples covering the Elecsys ASD assay measuring range; Passing-Bablok regression and Pearson’s correlation were calculated. Reference ranges were determined in five clinical cohorts using samples from several sites/vendors: apparently healthy children (≤ 8 years [US vendor]); apparently healthy women with proven fertile cycle (US, 22–37 years [Trina Bioreactives AG, USA; Roche Wellness Center, USA]; EU/ROW, 18–37 years [UZ Brussel, Belgium; University Hospital Leipzig, Germany; Practice Dr Rohsmann, Germany]); apparently healthy men (≥ 18 years [Bavarian Red Cross, Germany]); post-menopausal women (55–70 years [NUVISAN GmbH, Germany]); and women with PCOS (18–45 years [Medical University of Graz, Austria]).

Results: Repeatability and intermediate precision CVs across all sites were 2.01–3.91% and 2.43–4.30%, respectively (mean ASD concentrations 2.23–9.92 ng/ml). The Elecsys ASD assay showed poor correlation with IMMULITE ASD (slope = 0.459; r = 0.856; n = 320), moderate correlation with LIAISON ASD (slope = 0.625; r = 0.984; n = 327), and very good correlation with ID-LC-MS/MS (slope = 1.040; r = 0.996; n = 332). Reference ranges (5th–95th percentiles): apparently healthy children (n = 140), <0.150–0.382 ng/ml; apparently healthy women (n = 84), 0.490–1.31 ng/ml; apparently healthy men (n = 138), 0.355–1.26 ng/ml; post-menopausal women (n = 140), 0.208–0.990 ng/ml; women with PCOS (n = 125), 0.756–3.03 ng/ml.

Conclusion: The Elecsys ASD assay demonstrated excellent precision and very good correlation with ID-LC-MS/MS. Reference ranges were established to support results interpretation in routine clinical practice.