Measuring testosterone in women and men.

Measurement of serum testosterone (T) level is of utmost importance for the evaluation of hypogonadism in men and androgen excess in women. Despite the advances in steroid hormone assessment, substantial variability exists regarding measurement of T concentrations. Several factors affect T measurement in men, including circadian rhythms, intra-individual daily variability and transient stressors, while T concentrations in women vary mainly according to the phase of the menstrual cycle. Most of the available immunoassays lack the required accuracy when dealing with T concentrations at the lower end of the normal range for men and across the entire range for females. Consequently, there is no universally accepted lower T threshold for healthy adult men and most immunoassays fail to detect states of mild androgen excess in women. Mass spectrometry is considered the gold-standard method for T measurement; however, due to its complexity and cost, it has not been widely adopted. To increase accuracy, T in men should be measured with a fasting morning sample and repeated if the level is found to be low; in women, measurement must be performed at the follicular phase of the cycle. In both cases, borderline results may be clarified by the assessment of free testosterone (fT). Since most fT assays are unreliable, calculated surrogates should be used instead. Collaborative efforts have been undertaken, with rigorous internal and external quality controls and the establishment of reference methods, to harmonise the commercial assays.

Testosterone replacement therapy: For whom, when and how?

The finding of low circulating testosterone level in men is relatively frequent. The symptoms of hypogonadism are very frequent in the aging men. However, the diagnosis of hypogonadism is often neglected and the opportunity to replace low testosterone in older men is highly debated. The aim of this narrative review is to summarize the steps necessary to formulate a proper diagnosis and to guide toward an individualized treatment. While universally recognized the need to treat the young adults with known causes of pituitary or testicular failure, there are controversies on the cost-benefit of treating testosterone deficiency in older men. Discrepancies among the several available guidelines do not help to clarify the scenario, however, the recent larger clinical trials have shed some light on the fact that testosterone treatment carries some benefit, that is not free from risks. We provide an updated review of the diagnostic hallmarks, the several treatment modalities, with their advantages and disadvantages, and how to individualize and monitor treatment in order to maximize the benefits and minimize the risks. The treatment of male hypogonadism can no longer be downgraded and must become part of the cultural baggage of the endocrinologist.