The hypoosmotic test is a test to assess sperm vitality, although it is a technique little used today. It involves putting the sperm in a hypotonic medium, which causes an osmotic imbalance between the extracellular and intracellular medium.
In this way, it is possible to distinguish between:
- Live spermatozoa: they react to the change of medium, causing the tail to curl.
- Dead spermatozides: they do not react to the hypotonic medium, so they show the smooth thing.
To obtain a reliable result of the vitality test, it is necessary to study at least 200 sperm. When the percentage of live sperm is greater than 58%, it will be said that the sperm vitality is correct. However, if the percentage of live sperm is less than 58%, the seminal sample will be diagnosed as necrozoospermia.