Endocrine Abstracts

Testosterone, androstenedione and DHEAS are commonly measured by immunoassays. Variations in antibody specificity and calibration of assays results in non-commutability of measurements. Even more specific mass spectrometry (LC–MS/MS) assays still exhibit differences in calibration. As the use of mass spectrometry for measuring steroids is becoming more common in the clinical laboratory, the development of LC–MS/MS reference ranges for these analytes is essential to help accurately identify patients with abnormal serum concentrations, indicating possible disease states.

In order to generate reference ranges, serum samples from 92 healthy female and 94 healthy male volunteers aged between 16 and 74 were analysed for testosterone, androstenedione and DHEAS by LC–MS/MS. The data was analysed using Analyse-it for Microsoft Excel. The data showed testosterone, androstenedione and DHEAS were not normally distributed in both male and females and therefore ranges were determined non-parametrically with 95% confidence intervals. The female reference ranges for testosterone, androstenedione and DHEAS were 0.3–1.68 nmol/l, 0.85–6.0 nmol/l and 0.4–5.8 μmol/l respectively. The male reference ranges for testosterone, androstenedione and DHEAS were 8.4–30.9 nmol/l, 1.5–7.4 nmol/l, and 1.3–13.4 μmol/l.

As the majority of clinical laboratories use immunoassay, cascade testing is common when investigating the androgen status of an individual, therefore it is essential to use accurate reference ranges. The reference ranges found in our LC–MS/MS assays are lower than those found in immunoassays highlighting the lack of specificity of these assays. Mass spectrometry has the flexibility to allow the measurement of multiple analytes in a single assay, negating the need for cascade testing. We have developed accurate reference ranges to quickly and comprehensively assess the androgen status of an individual.