Brian G Keevil1, Jo Adaway1, Tom Fiers2, Paolo Moghetti3, Jean-Marc Kaufman2. 1. Department of Clinical Biochemistry, Manchester University Hospital NHS Trust, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK. 2. Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium. 3. Endocrinology, Diabetes and Metabolism, Department of Medicine, University and AOUI of Verona, Verona, Italy.
Abstract
OBJECTIVE/CONTEXT: The free androgen index (FAI) is known to give erroneous results in men, but it is still a commonly used test for the investigation of hyperandrogenism in women. This study aimed to compare the results of the FAI with the gold standard equilibrium dialysis method for free testosterone in women. DESIGN/PATIENTS: Free serum testosterone T (ED-T) and total serum T (T) were measured by equilibrium dialysis and LC-MS/MS in patients with polycystic ovarian syndrome (n = 130), normal female controls (n = 53) and normal males (n = 120). Calculated free T (cFT) and free androgen index (FAI) were also measured in these patients. In addition, cFT was retrospectively calculated in 4223 female patients with a normal T (<1.6 nmol/L) routinely investigated for hyperandrogenism. RESULTS: The cFT showed good agreement with measured ED-T, and the ratio cFT/ED-T was stable across all SHBG concentrations. In contrast, the FAI/ED-T ratio and the FAI/cFT ratio increased when the concentration of SHBG fell below 30 nmol/L. CONCLUSIONS: The FAI is not a reliable indicator of free T when the SHBG concentration is low and would give misleading information in a large number of women being investigated for hyperandrogenism.
OBJECTIVE/CONTEXT: The free androgen index (FAI) is known to give erroneous results in men, but it is still a commonly used test for the investigation of hyperandrogenism in women. This study aimed to compare the results of the FAI with the gold standard equilibrium dialysis method for free testosterone in women. DESIGN/PATIENTS: Free serum testosterone T (ED-T) and total serum T (T) were measured by equilibrium dialysis and LC-MS/MS in patients with polycystic ovarian syndrome (n = 130), normal female controls (n = 53) and normal males (n = 120). Calculated free T (cFT) and free androgen index (FAI) were also measured in these patients. In addition, cFT was retrospectively calculated in 4223 female patients with a normal T (<1.6 nmol/L) routinely investigated for hyperandrogenism. RESULTS: The cFT showed good agreement with measured ED-T, and the ratio cFT/ED-T was stable across all SHBG concentrations. In contrast, the FAI/ED-T ratio and the FAI/cFT ratio increased when the concentration of SHBG fell below 30 nmol/L. CONCLUSIONS: The FAI is not a reliable indicator of free T when the SHBG concentration is low and would give misleading information in a large number of women being investigated for hyperandrogenism.
Authors: Susan F Evans; Yuen Kwok; Ann Solterbeck; Carmen Pyragius; Mary Louise Hull; Mark R Hutchinson; Paul Rolan Journal: J Pain Res Date: 2021-03-03 Impact factor: 3.133
Authors: Dina B Stensen; Lars Småbrekke; Karina Olsen; Guri Grimnes; Christopher Sivert Nielsen; Johanna U E Sollid; Gunnar Skov Simonsen; Bjørg Almås; Anne-Sofie Furberg Journal: Eur J Endocrinol Date: 2021-02 Impact factor: 6.664
Authors: Michael W O'Reilly; Marija Glisic; Balachandran Kumarendran; Anuradhaa Subramanian; Konstantinos N Manolopoulos; Abd A Tahrani; Deepi Keerthy; Taulant Muka; Konstantinos A Toulis; Wasim Hanif; G Neil Thomas; Oscar H Franco; Wiebke Arlt; Krishnarajah Nirantharakumar Journal: Clin Endocrinol (Oxf) Date: 2018-10-23 Impact factor: 3.478
Authors: Jon J Rasmussen; Christian Selmer; Signe Frøssing; Morten Schou; Jens Faber; Christian Torp-Pedersen; Gunnar H Gislason; Lars Køber; David M Hougaard; Arieh S Cohen; Caroline Kistorp Journal: J Endocr Soc Date: 2020-05-05
Authors: Alexandra Lenoir; Elaine Fuertes; Francisco Gómez-Real; Benedicte Leynaert; Diana A van der Plaat; Debbie Jarvis Journal: ERJ Open Res Date: 2020-09-28