Assessing hypogonadism in men--how helpful are current testosterone assays?

Area of Science:

• Endocrinology
• Andrology
• Men's Health

Background:

• Testosterone therapy (HT) is increasingly used for aging men, showing benefits in body composition.
• It can decrease fat mass and increase lean body mass in men with testosterone deficiency.

Observation:

• The Australian Pharmaceutical Benefits Scheme (PBS) subsidises male HT based on specific testosterone level cut-offs (<8.0 nmol/L or 8-15 nmol/L with elevated luteinising hormone [LH]).
• The scientific rationale for these precise cut-offs is not clearly established.
• Testosterone levels exhibit diurnal and seasonal variations, which the PBS criteria attempt to mitigate by requiring two morning blood samples.

Findings:

• The current PBS criteria for testosterone replacement therapy are based on arbitrary cut-offs.
• These cut-offs may not align with the lower limits of normal testosterone levels across all laboratories.
• The reliance on morning samples aims to standardize measurements but doesn't fully address inherent hormonal fluctuations.

Implications:

• Further research is needed to establish evidence-based guidelines for testosterone therapy eligibility.
• Current diagnostic criteria may require re-evaluation to ensure optimal patient selection for hormone therapy.
• Standardizing testosterone level assessments across different laboratories is crucial for accurate diagnosis and treatment.