How Is the Sperm Actually Frozen?

Frozen sperm must be stored in extremely cold temperatures (-196 F), but in order to ensure that the fewest possible sperm are damaged, the freezing must be gradual. Generally, the following procedure is followed:

  1. If the sperm hasn’t been previously tested, a comprehensive semen analysis should be performed on the first specimen in order to provide a complete picture of the sperm quantity and quality. Make sure that the sperm bank conducts a thorough semen analysis before banking. This will give you significant information on the quality of the sperm.
  2. Each subsequent specimen is analyzed prior to freezing to assess total number of moving sperm.
  3. Immediately after the specimen is analyzed, it is divided into smaller batches and transferred into vials for freezing. A special compound (a cryoprotectant) is added to aid the freezing process.
  4. The test tubes are gradually frozen in liquid nitrogen vapor. After 30-60 minutes they are transferred into liquid nitrogen tanks for permanent frozen storage.
  5. After a minimum of 48 hours have elapsed from the time of the initial freezing, an initial “test sample” is thawed and tested again to ascertain from each specimen how well the sperm survived the freezing. After the banking is complete, the results may be sent to you, as well as possibly discussed with your primary care physician. This information will be important to determine which specimen vials to thaw for an insemination.

Each sample is stored in its own specially marked storage unit. Some cryobanks split the specimens, storing half of any individual’s specimens in two separate nitrogen tanks in case of tank malfunction. Some may actually store the two tanks on separate physical sites in case of an unforeseeable disaster to the building in which a tank is stored. The nitrogen tanks are checked daily for temperature and liquid nitrogen leakage.

If you are interested in banking your sperm, but would like to know if your sperm is viable and worth banking , click here.

If you seeking a sperm donation, or are a prospective donor, here is a list of sperm banks by location.