INFERTILITY DIAGNOSIS Article · 11 July 2022

Sperm under the microscope – a few words about semen analysis

The semen test is the basic test for assessing male fertility and necessary in case of problems with getting pregnant. Doctors recommend taking a seminogram usually after about 1 year of trying to conceive. In the so-called seminological examination semen quality is assessed according to criteria proposed by the WHO.

semen analysis

Although the sperm is almost 20 times smaller than an egg, because it measures about 0.006mm long with a tail, it plays an extremely important role. It is impossible to conceive a child without its participation. However, before the inconspicuous sperm meets the egg, flowing towards it at a speed of 0.1mm / s (and tail waving 800 times  at the distance of each centimeter swam) to rise a new life, it must pass a real test of endurance and overcome many obstacles on its way and millions of competitors.


That is why it is so important that the spermatozoa, when starting the race for the egg, is in the best condition. Fortunately, you can check the quality of spermatozoa with a simple and painless examination – of course, we are talking about a seminogram.


The semen test is the basic test for assessing male fertility…


…and necessary in case of problems with getting pregnant. Doctors recommend taking a seminogram usually after about 1 year of trying to conceive. In the so-called seminological examination semen quality is assessed according to criteria proposed by the World Health Organization (WHO).


Sperm – the most important component of sperm


Continuous production of male reproductive cells begins at the time of puberty of a young man, around 12-13 years of age. It runs under the control of the endocrine system in the even testicles located in the scrotum (at a temperature 1.5 °C lower than in the center of the body). More precisely, the process of spermatogenesis occurs in sperm-forming tubules at a release rate of approx. 3,000 spermatozoa per 1s. Finally, sperm during ejaculation (ejaculation) are suspended in the nutritious and protective semen plasma – liquid secretion produced by the testicles and epididymis (5%), seminal vesicles (46-80%), prostate (13-33%) and bulbous-tubular glands and urethral glands (2-5% volume). Plasma abounds, among others in testosterone (the basic male sex hormone), fructose (sugar, energy), the enzyme PSA (liquefies sperm and releases sperm from the plasma in the vagina), lubricants and antibodies.


However, before one sperm can fertilize an egg, it must (like millions of others) reach the required maturity within 74 days. It is preceded by a series of divisions of primary germ cells and a number of changes that lead to the formation of actively floating spermatozoa with a head (containing 23 chromosomes with genes) and an acrosome (dissolving oocyte covers), the neck, midpiece (in which mitochondria responsible for providing energy) and tail (providing sperm drive).


Sperm test – what exactly is checked?


The semen analysis consists of two stages. In the first, the male ejaculate is subject to andrological macroscopic evaluation. It includes such parameters of the donated sperm sample as: volume of ejaculate, liquefaction time, color and smell, viscosity and pH. The second stage, i.e. microscopic evaluation, determines the total number of sperm in the semen, in 1mm, motility, viability and structure (morphology).


How much semen must be donated to make the sample suitable for analysis?


To be able to perform a complete semen analysis, the analyzed sperm sample deposited by the patient in a comfortable cup must have a certain minimum volume. Usually, the norm is 2-5 ml, or at least 1.5 ml after ejaculation (1/3 teaspoon), which is affected by the condition of the man and the period of sexual abstinence. The preferred period for sperm sexual abstinence is 2-7 days, optimally 3. If the period of sexual abstinence is too short, the number of spermatozoa may be lower, if the period of sexual abstinence is too long, the number of spermatozoa may be higher, but motility, vitality and morphology will be significantly impaired. Despite the recommendations, too small volume of ejaculate may suggest retrograde ejaculation or the presence of anatomical defects within the reproductive organs of a man. Too much ejaculate volume and possible sperm thinning are also not desirable.
How much sperm should there be in the semen?


According to WHO recommendations, “normal” semen parameters are assumed (lower limit, 5th centile):

Volume of ejaculate (sperm) ≥ 1.5 ml
Total sperm count in ejaculate ≥ 39 million
Sperm concentration (sperm count in 1 ml of semen) -+0+15 million / ml
Mobility (progressive – fast, progressive / non-progressive) 40%
D-type sperm motility (stationary) <60%
Progressive spermatozoa (A + B) ≥ 32%
Viability – (% live sperm) ≥ 58%
pH ≥ 7.2
Sperm morphology (structure test) – ≥ 4% of normal forms
Leukocytes test with preoxidase <1 million (if the semen contains a large number of white blood cells, this may indicate an existing infection or inflammation)
Immunobead test (its purpose is to detect sperm antibodies in an amount that disrupts sperm function) <50%
Fructose (energy resource for sperm) ≥ 13 mmol / ejaculate


It should be noted that these are not reference values (based on statistics). These values do not set a threshold below which a man is infertile and cannot have children – his chances may simply be lower.


If abnormalities are found as a result of semen analysis, they should be repeated within one to three months (this is the time of sperm maturation).


What is the liquefaction time?


Semen coagulates almost immediately after ejaculation, forming a viscous, gelatinous liquid. It liquefies again after 5 – 40 minutes. A semen sample can be delivered from home to the laboratory. In order for the test result to be reliable, the semen should be analyzed at the latest within 1 hour of ejaculation, i.e. immediately after liquefaction. Sometimes the semen does not liquefy, which prevents its further analysis. Then the employee of the andrological laboratory may subject the ejaculate to additional processing.


How much sperm color and smell says about a man’s health?


It turns out that quite a lot! The semen is usually milky white or grayish, occasionally yellowish (too yellow may indicate jaundice or come from medication). Pink or red semen suggests the presence of blood. Greenish sperm color, in turn, can occur with bacterial infections.


Sperm, cadaverine, putrescine and spermidine, which is part of the semen, give it a characteristic taste and smell (edible chestnuts), while their physiological task is to protect the sperm DNA against the acidic environment of the vagina. The unpleasant smell of sperm can be caused by an infection of the male reproductive system, therefore medical advice is always required sperm crystallizes after drying out (spermine phosphate crystals).


When the semen is too sticky…


The correct semen flows from the diagnostician’s pipette with sticky drops. However, if it’s  too sticky to create threads that extend over 2 cm it can indicate a disease state, e.g. cystic fibrosis. It may also be associated with prostate disease or inflammation in the male reproductive system, or indicate dehydration.


Sperm do not like acid environment


Male sperm should have a slightly alkaline pH (7.2 and 7.6). Such conditions ensure adequate sperm motility, which they acquire during puberty in the epididymis (14 days). For comparison, a woman’s vagina has a strongly acid pH (3-5). And that’s why a large proportion of spermatozoa die in the acidic environment of the vagina just after ejaculation. The cause of too low semen pH may be a disease state located within the seminal vesicles. In turn, alkaline semen (above pH 8) may indicate prostate problems.


How fast should the sperm move?


It might seem that the sperm moving at a speed of about 0.1 mm / sec. doesn’t make it some outstanding sprinter. However, taking into account its truly microscopic dimensions and the path of a few centimeters that it has to cover through the vagina, the uterus towards the oocyte deposited at the end of the fallopian tube (through the specifically formed mucus), the sperm moves really fast. The quality of the male cell’s movement is definitely important. When assessing sperm motility, three states of movement are taken into account – progressive (flows forward), non-progressive (sperm moves in place), and no movement.


At least 40% of spermatozoa should be in normal sperm, while according to the criteria of the World Health Organization, 32% of spermatozoa should move in a progressive motion. Sperm can move abnormally for many reasons. The cause may be an “unhealthy” lifestyle, including nicotinism and inhalants, alcohol, prostate disease, inflammation, the presence of anti-sperm antibodies, varicocele, dehydration, genetic diseases (including cystic fibrosis – thick mucus, Kartagener Syndrome).


At least 4% of spermatozoa should have normal structure…


to meet the lower limits of the norm (5th centile) currently recommended by WHO to fulfill its biological role – DNA transfer. Morphological abnormalities can affect any part of the sperm – head, neck, midpiece or tail – and have very different nature and origin. For example, the head may be too small, too large, have the wrong shape, improperly shaped acrosome, it may not be present (“spermatozoon”), there may be two heads. A correctly developed sperm head is of cardinal importance for the transmission of genetic information, because the sperm head has a cell nucleus with 23 chromosomes, which when combined with an egg (with 23 chromosomes) recreates the correct composition of the first cell of the future child (46 chromosomes) and all subsequent ones. If the head is improperly formed or subsequent parts of the sperm associated with its drive, then the natural conception of a child can be very difficult or even impossible.


Basic semen analysis


Basic semen testing is done using CASA (Computer Assisted Semen Analysis) technology. Semen is analyzed in cooperation with an automatic computer system SCA (Sperm Class Analyzer). The microscopic image, recorded by a video camera, is processed and subjected to digital computer analysis “under the watchful eye of an andrologist”. The result panel obtained in this way allows to correctly and very accurately assess the most important sperm parameters (concentration, motility and morphology of spermatozoa), which is of great diagnostic importance (healthy / sick).


To assess oxidative stress in semen, a very accurate and fast MIOXSYS test is used. Oxidative stress is currently one of the most important factors of male infertility. It is based on an imbalance between the amount of free radicals (harmful products of metabolism) and the body’s ability to remove them. MIOXSYS allows to evaluate this ability.


MSOME examination and sperm DNA fragmentation


Further analysis for semen evaluation is enabled by the MSOME test, which tests sperm at an magnification of 6000-8000 times and the SCD test. The last of these, i.e. the study of DNA fragmentation of sperm, allows you to assess damage to their genetic material. This is a very important parameter because the presence of any abnormalities in the germ cell DNA significantly reduces the chance of fertilization, and also increases the risk of pregnancy loss and the birth of a child with a genetic defect.


Sperm quality and infertility


The correct semen test result does not mean that a man can become a father 100%. It is estimated that 40% of male infertility cases are caused by reduced sperm production or “worse” sperm quality. Other causes of male infertility may include, for example, damage to the testicles or vas deferens as a result of infection (e.g. gonorrhea) or trauma, and even heart, lung and kidney disease. In turn, the results of the semen test, in which the parameters are significantly below normal, do not mean male infertility. A patient with significant sperm parameters, e.g. sperm count below normal, has a chance of becoming a father.


The quality of the semen changes over time and under the influence of various external factors (stress, diseases, diet, stimulants, low physical activity, harmful factors related to work, etc.). Therefore, sperm diagnosis should be based on several results obtained. A single semen test result does not entitle the patient to be classified as sterile.


So what should a man do to get his partner pregnant?


Many causes of infertility can now be avoided. For example, surgery for varicocele or repair of obstructed vas deferens contributes to the return of chances for natural fertilization of the partner. Intrauterine insemination, sperm conditioning and increasing sperm concentration are proposed for men with lower than normal sperm counts. A whole range of ART and IVF treatments is also available.

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