Reproductive Endocrinology Reference Intervals for Transgender Men on Stable Hormone Therapy

Area of Science:

• Endocrinology
• Transgender Health
• Clinical Chemistry

Background:

• Gender-affirming hormone therapy, specifically testosterone, is common for transgender men.
• Interpreting sex-hormone concentrations is challenging due to a lack of established reference intervals.
• Accurate interpretation requires population-specific reference ranges.

Purpose of the Study:

• To establish reference intervals for commonly measured sex hormones in transgender men receiving testosterone therapy.
• To guide clinical interpretation of endocrine laboratory tests in this population.
• To improve the quality of care for transgender individuals.

Main Methods:

• Recruited 82 healthy transgender individuals on testosterone for at least one year.
• Measured total testosterone, estradiol, LH, FSH, SHBG, prolactin, progesterone, AMH, and DHEAS.
• Calculated reference intervals (central 95%) following CLSI guidelines.

Main Results:

• Reference intervals for cisgender men can be used for total/free testosterone and SHBG.
• Reference intervals for cisgender women can be used for prolactin.
• Estradiol, LH, FSH, AMH, and DHEAS require specific transmasculine population intervals for accurate interpretation.

Conclusions:

• Masculinizing hormone therapy significantly alters endocrine hormone concentrations.
• Providers and laboratories must utilize appropriate, population-specific reference intervals for accurate test interpretation.
• This study provides critical data for the clinical management of transgender men on testosterone therapy.