INTRODUCTION
Male hypogonadism is a clinical syndrome characterised by testosterone deficiency and impaired spermatogenesis; due either to diseases of the hypothalamus or pituitary gland, or of the testes themselves.1 The diagnosis requires the presence of clinical features consistent with lack of testosterone plus the finding of persistent and unequivocally low serum testosterone levels. Failure to recognise and treat men with hypogonadism may predispose them to long-term health problems, such as anaemia, osteoporosis, depression, or sexual dysfunction.
Over recent years, there has been a surge in testosterone prescriptions for men with sexual dysfunction or putative age-related decline in testosterone,2 possibly reflecting pharmaceutical promotion, or sharing of misleading information on the internet. With growing demands and expectations of men worried about their wellbeing, there is a real risk of overdiagnosis and unnecessary treatment with testosterone. Suboptimal sampling conditions can lead to misinterpretation of serum biochemistry, and the long-term risks of testosterone therapy for men not having verified hypogonadism may be underestimated by ‘enthusiasts’.
DIAGNOSTIC CHALLENGES
Diagnosis of hypogonadism
Routine screening for hypogonadism in asymptomatic men is not recommended, except in certain conditions (Supplementary Figure S1). Clinical features of hypogonadism are not limited to sexual symptoms — reduced libido, erectile dysfunction (ED), and loss of waking erections. Anaemia, osteoporosis, and vasomotor sweating or flushing are frequently present; indeed, older men may not volunteer sexual symptoms, having ascribed them to ageing.
Sampling conditions
Testosterone secretion has diurnal variation and is suppressed post-prandially, so serum testosterone and sex-hormone binding …