Introduction
Polycystic ovary syndrome (PCOS) is a prevalent disorder, affecting 5-20% of premenopausal women. Metabolic and reproductive subtypes of PCOS based on clinical and biochemical phenotype have been described (1).
Elevated androgens are the biochemical hallmark of PCOS, with hyperandrogenism noted in >70%, either elevated total testosterone or free androgen index (FAI)(2). Testosterone levels vary according to age and weight, menstrual phase, or as measured by LCMS or immunoassay (IA).
Methods
Androgen assays results performed at PathWest QE2 Medical Centre between January 2020-2022 from females between 18-40 years were extracted. Testosterone assays were performed primarily by Abbott Architect IA. Results above reference intervals - testosterone ≥ 2 nmol/L or FAI ≥6 - were included. Transgender results were excluded.
Results
There were 4730 IA testosterone results, 98 also with LCMS measurement – LCMS/AI correlation (R2=0.76). 737 females had increased FAI ≥6 and 460 testosterone ≥2 nmol/L. Of those with testosterone ≥2 nmol/L, 217 were identified as PCOS/?PCOS on the request form. High FAI was contributed to by high total testosterone (284/737), or low SHBG (632/737), or both (187/737). Of 165 women with PCOS/?PCOS in follicular phase, 59 had an LH/FSH ≥2, of whom 44 had increased FAI and 27 a low SHBG (see Table 1).
Conclusion
The correlation between IA and LCMS testosterone supports IA to assess hyperandrogenism in women. The majority of females with PCOS/?PCOS had a mildly elevated testosterone (2-3 nmol/L). Among them, 19% had an elevated LH/FSH ratio ≥2 with normal or higher SHBG (reproductive subtype), while 35% had a normal LH/FSH ratio with reduced SHBG (metabolic subtype). Even so, significant biochemical heterogeneity highlights the need for improved PCOS phenotype characterisation.