Redefining testosterone reference ranges for adult females

Area of Science:

• Endocrinology
• Reproductive Health
• Biostatistics

Background:

• Testosterone (T) plays a role in female physiology.
• Accurate reference ranges for female T are lacking, hindering clinical diagnosis.
• Age-related changes in female T are not well-defined.

Purpose of the Study:

• To establish a robust, age-continuous reference range for testosterone in adult females.
• To provide a tool for differentiating physiological and pathological T levels.
• To analyze age-specific T distributions and identify trends.

Main Methods:

• Retrospective analysis of serum T from 5,323 females (19-59 years).
• Inclusion criteria: no reproductive conditions, normal BMI, regular cycles.
• Statistical modeling to determine age-continuous reference ranges and compare with a hirsutism cohort.

Main Results:

• A weakly skew-Normal distribution best fits log T values, with mean T decreasing and variance increasing linearly with age.
• Significantly higher T levels were observed in females with self-reported hirsutism compared to the reference group.
• Established a robust, age-continuous reference range for female T.

Conclusions:

• The developed reference range is essential for accurate clinical assessment of female T levels.
• Highlights the significant decline in testosterone over adult female lifespan.
• A valuable resource for clinicians and researchers for comparing patient hormone levels.