This is basically a test of the swimming ability (motility) and fitness of the sperm. It is usually carried out in conjunction with a semen analysis and involves the washing of sperm in a special liquid or culture media and then a measurement of their ability to swim-up into a fresh layer of media.
This test gives an indication of the ability of the sperm to reach the egg under normal conditions. It allows the clinician to choose the best treatment option to assist the couple conceiving. The sperm which is suitable for IUI is also suitable for IVF. If the sperm fails the swim up test, it can only be suitable for ICSI. A normal swim up test cannot guarantee normal fertilisation rate with IVF. About 5% of the couples have low or failed fertilisation with IVF despite normal sperm.