TESA or Testicular sperm Aspiration is one of the surgical sperm harvesting techniques used for retrieving sperm in patients with azoospermia. A number of surgical sperm retrieval or recovery methods have been devised to recover sperm from the male reproductive tract. In men who have obstructive azoospermia which may be due to duct blockage or absence of the vas deferens, sperm is generally recovered from the epididymis.

The doctor using the simple butterfly needles punctures the epididymis, a technique which was very similar to drawing blood from the blood vessel. By PESA (percutaneous epididymis sperm aspiration) in which sperm is sucked out from this epididymis by puncturing it with a fine needle. The process takes place under local anesthesia. The testicular tissue is placed in culture media and send to the lab, where it is processed. The sperm is librated from within the seminiferous tubules and are then dissected free from the surrounding testicular tissue.