The Halosperm Test


While the routine semen analysis can provide important information about male fertility such as sperm concentration and motility, it does not reveal any information about the integrity of the sperm’s DNA.

Sperm DNA can be damaged by exposure to chemicals, smoking, high temperature and free radicals from normal metabolism. Sperm DNA fragmentation has been associated with decreased fertilization rate and miscarriages.

Research has shown that broken DNA in sperm does not disperse after acid denaturation. In contrast, normal sperm DNA disperses after special acid treatment to produce a halo of DNA chromatin around the sperm head.

The Halosperm test makes use of this property to differentiate sperm with normal DNA from those with fragmented DNA. Sperm are first exposed to a colored agent that stains the DNA within the sperm capsule. Subsequent acid treatment makes the sperm membrane leaky. Like a coiled spring upon release, sperm DNA disperses quickly through the leaky membrane to form a halo around the head of the sperm. If the DNA coil is broken, it does not leak readily through the sperm membrane and thus remains confined within the sperm head.

Sperm that do not show the halo by the Halosperm test are thought to contain broken DNA. When 30% or more sperm have fragmented DNA, the sample is considered to be abnormal.


In cases of high sperm DNA fragmentation, we use the PICSI technology to increase the chance of picking up a normal sperm for ICSI. We recommend antioxidants to men with abnormal Halosperm test results for at least 3 months to minimize the harmful effect of free radicals on sperm DNA.

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