What is the definition of oligospermia that necessitates endocrine workup in males?

Oligospermia refers to a lower than normal sperm concentration in a male's semen. The threshold for diagnosing oligospermia is generally considered to be less than 15 million sperm per milliliter, based on the World Health Organization's criteria. However, in clinical practice, particularly when considering the need for an endocrine workup, more severe levels of oligospermia are often focused upon.

In this context, a sperm concentration of less than 10 million per milliliter is often significant and warrants further evaluation, including an assessment of hormonal levels to rule out underlying endocrine disorders, which may be contributing to the low sperm count. Hormonal imbalances, such as hypogonadism or problems with the hypothalamic-pituitary-gonadal axis, can lead to severely reduced sperm production.

Thus, a sperm concentration of less than 10 million/mL is a critical threshold that typically necessitates a comprehensive endocrine investigation to identify possible reasons for the infertility and to inform the subsequent management of the patient.