How is sperm stored?

After a sperm sample is collected, it is tested for:

  • Sperm concentration
  • Sperm motility (the number of live, swimming sperm)
  • Sperm forward progression (the sperm’s rate and speed of forward movement)
  • Viscosity (the liquidity of the ejaculate; thicker semen makes it more difficult for sperm to travel)
  • Sperm Morphology (the percentage of sperm that have a normal oval shape)
  • pH
  • White blood cell count (high blood cell counts may indicate infection)

After testing the sperm may be washed, which concentrates the sperm and removes dead cells.  Finally, it is then stored in small vials or straws and cryogenically preserved in liquid nitrogen tanks.