The Simultaneous measurement of serum testosterone and 5α-dihydrotestosterone by gas chromatography–mass spectrometry (GC–MS)

Kannenberg F., Fobker M., Schulte E., Pierściński G., Kelsch R., Zitzmann M., Nofer J., Schüring A.

Zusammenfassung

Background Simultaneous measurement of testosterone (T) and 5α-dihydrotestosterone (DHT) is important for diagnosing androgen deficiency states and hyperandrogenism in males and females, respectively. However, immunoassays used for T and DHT determination suffer from inadequate specificity and sensitivity, while tandem mass spectrometry is expensive and demanding in use. Methods and results We developed a selective gas chromatography–mass spectrometry (GC–MS) method for parallel T and DHT measurement. The assay showed a linear response up to 46.5 nmol/L, intra- and interassay imprecision and inaccuracy < 15% and recoveries in spiked samples > 90% for both analytes. The limit of quantitation was 0.117 nmol/L for T and 0.168 nmol/L for DHT. Comparison with immunoassays revealed good agreement for T in males, but a bias in favour of immunoassays at low concentrations for T in females and DHT in both sexes. We established reference ranges for T and DHT and suggest interval partitioning for T according to age in men and menstrual cycle in women. Assay validation in a clinical setting suggests that measuring DHT or T/DHT ratio may help identify patients with polycystic ovary syndrome. Conclusion We developed a selective, simple and inexpensive GC–MS method for parallel measurement of T and DHT with potential use in the clinical laboratory.