After collection, sperm must be processed for storage. According to the Sperm Bank of California, sperm banks and clinics can use the unwashed or wash method to process sperm samples. The wash method includes removing unwanted particles and adding buffer solutions to preserve viable sperm. However, this approach can contribute to further stress on the sperm cells and decrease the survival of sperm after freezing. The unwashed approach allows for more flexibility to freeze the semen sample and increases the number of sperm survival. One sample can produce 1–20 vials or straws, depending on the quantity of the ejaculate and whether the sample is washed or unwashed. Unwashed samples are used for intracervical insemination (ICI) treatments, and washed samples are used in intrauterine insemination (IUI) and for in-vitro fertilization (IVF) or assisted reproduction technologies (ART) procedures.
A cryoprotectant semen extender is conducted if the semen sample is placed in the freezer for storage. Semen extenders play a key factor in protecting sperm sample from freeze and osmotic shock, oxidative stress, and cell injury due to the formation of ice crystal during frozen storage. The collection of semen is preserved by stabilizing the properties of the sperm cells such as the membrane, motility, and DNA integrity in order to create a sustainable viable environment. There are two common forms of medium for sperm cyropreservation, one containing of egg yolk from hens and glycerol, and the other containing just glycerol. One study compared media supplemented with egg yolk and media supplemented with soy lecithin, finding that there was no significance between sperm motility, morphology, chromatin decondensation, or binding between the two, indicating that soy lecithin may be a viable alternative to egg yolk.