Aims
To determine whether identification of women of PCOS differs between the use of tT measured by LC-MS/MS or a commercially available immunoassay.
Methods
A sub-group of participants in the Grollo-Ruzzene Study of Young Women’s Health were invited to a sub-study which involved a pelvic ultrasound, a blood sample for serum tT by both LC-MS/MS and immunoassay (Abbott Architect Gen II) and questions about their menstrual cycle. Participants were classified as having PCOS according to Rotterdam criteria, with the LC-MS/MS tT as the reference.
Results
Of 1121 potential participants, 240 wished to participate and met the inclusion criteria and 168 had a blood sample and ultrasound. None of the 15 women with tT above the LC-MS/MS reference range were also above the reference range of the immunoassay, and no women within the LC-MS/MS reference range had an elevated immunoassay tT. Most participants with an LC-MS/MS tT just above the cut-off were considerably below the immunoassay cut off.
Replacing LC-MS/MS tT results with immunoassay tT, reduced the number of women classified as having PCOS from 31 to 26 due to 3 participants being reclassified as polycystic ovary morphology only and 2 to menstrual dysfunction only. In addition, 2 participants with all 3 criteria were reclassified as only having 2 criteria for PCOS. None of the 137 women not classified as having PCOS by LCMS were reclassified as having PCOS by the immunoassay.
Conclusion
With limited availability of LC-MS/MS, which is considered gold standard for measurement of tT, clinicians should be aware that measurement of tT by the Abbott Architect Gen II may under-identify women with PCOS.