Male fertility is a major concern these days. Semen analysis is one of the important tests that can help find the root cause of infertility in men. Read on to know more about this test and how it is helpful.

Semen acts as the vehicle for a sperm's journey towards the female genital tract, and its analysis is designed to evaluate biological capacity like quality, number, motility, and morphology of the sperm to fertilize the egg. The formation of an embryo requires the cooperation between the functional properties of the sperm and the cyclic adaptations of the female reproductive tract. Human sperm has 3 parts - head, mid-piece and tail. The head of the sperm contains the nucleus that has the genetic information with a cap-like structure called the acrosome. The mid-piece houses the powerhouse that provides energy to sperm to move, and the tail helps the sperm to actually move toward the egg.

Semen analysis is the baseline test for infertility. It is designed to look at the number of sperms present in the semen, how well they move and what they look like. It is not a simple test and must be performed as per the WHO guidelines by a qualified technician or andrologist. Quality control and validation systems must be in place at the laboratory to maintain the reliability of the results.

How Is Semen Evaluated?

Semen is collected after an abstinence period of 2-7 days. Attention must be given for complete collection in a sterile wide-mouthed container meant for this purpose. The collection method must be through masturbation or sterile non-lubricated condom. The examination of the sample must be done within 60 minutes of collection. Semen parameters vary greatly in all men, and therefore at least 2-3 semen analyses are advised to establish an average for the person being investigated.

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The physical characteristics of the semen are examined first. The volume, time is taken for liquefaction, pH, colour, odour are noted. These characteristics may help understand the underlying problem especially when the count is low or when the sperms count is zero. A drop of semen is then examined under a microscope using a special glass slide. The concentration of sperms and motility is measured in a prescribed manner. Motility is evaluated in terms of progressive and non-progressive motility. When a sperm moves in and around the same area with no net movement, this is called non-progressive motility. Progressive motility refers to a movement that results in a net displacement of sperm albeit in a zig-zag manner. According to current WHO guidelines, for optimal fertility, sperm concentration should be more than 15 million per ml of semen. At least 40% of these must be motile, and 32% must have progressive motility.

Checking the sperm morphology or the shape of the sperm is an essential part of this test. Only a small minority of sperm have a normal shape and structure. The others may have a variety of abnormalities such as multiple tails, multiple heads, very small heads, large round heads, etc. The cut off for normality is the presence of 4% with normal structure when judged on the basis of strict Kruger's criteria. If not judged strictly a much larger number of sperms may appear normal, but this number cannot be correlated with infertility.

What Is A Sperm Function Test?

Sperm function tests are designed to determine if the biological function of the sperm is sufficient to allow the fertilization of the egg. These may be to check the penetration properties of sperm, the acrosome reaction, or the binding of the sperm to the eggshell. At present these tests are only considered as research tools and not available for clinical evaluation and decision making.

The real test of the biological function of sperm is conception, and currently, there are no tests that will confirm the functional competency of sperm. Hopefully, with advances in technology tests, this may become possible in future.