Sperm harvesting is entirely different from a diagnostic testicular biopsy because, in this setting, the goal is not to identify what is happening in the testis but instead it is to find sperm. Only men with no sperm in their ejaculate need to have sperm retrieved directly from the testis or epididymis.

This may involve a simple aspiration for men who have a blockage or require much more extensive sampling of the testis for men who have a sperm production problem.

Very few tests allow for an accurate prediction of whether or not sperm will be found in the testes of men with testicular problems. Typically genetic testing, hormonal studies and testicular ultrasound are performed before planning surgical sperm collection.

Performing the sperm retrieval in advance and freezing the sperm until the eggs are collected allows the couple to make an informed decision about whether to go forward with IVF, since in most circumstances the chance of finding sperm may be only 60 percent or less.

There are multiple surgical approach to sperm retrieval: testicular sperm aspiration (TESA), percutaneous sperm aspiration (PESA) and testicular sperm extraction (TESE).