Semen Analysis

SEMEN ANALYSIS

This is the most important test for evaluating seminal fertility. It assesses the quality of semen, which is collected through masturbation into a container provided by the laboratory, without the use of lubricants, as they may interfere with the sample.

A semen analysis can only be performed upon medical request in cases of suspected seminal infertility due to physical, genetic, or immunological conditions. Even individuals who already have children should undergo the test, as these conditions may have changed.

To perform the test, a period of sexual abstinence of 2 to 5 days is required, during which there must be no ejaculation through sexual intercourse or masturbation, to ensure the quality of the sample.
Various characteristics of the semen as a whole and of the sperm cells it contains are evaluated in the semen analysis through a descriptive report, as we will see below.

Color

Healthy semen has a uniform milky-white color. If it shows brownish tones, for example, it may indicate hematospermia (the presence of red blood cells in the semen).
Liquefaction

Normal semen samples liquefy, that is, become liquid, within one hour. If, at the end of this period, gelatinous granules are detected, forming a heterogeneous mixture, this is not considered ideal.
pH

Part of the liquefied semen is then placed on a pH test strip. In normal samples, the value ranges between 7.2 and 7.8. Samples below 6.5 may indicate the absence, malformation, or blockage of the seminal vesicles.
Viscosity

In a simple dripping test using liquefied semen, the sample is aspirated through a pipette to determine whether it forms regular drops. If the viscosity is abnormal, instead of drops, a 2 cm filament may form, which may indicate possible prostate dysfunction due to chronic inflammation.

This altered consistency may also interfere with the evaluation of several other semen characteristics in the following stages of the semen analysis, such as concentration, motility, and the detection of antisperm antibodies.
Volume

A normal ejaculation contains more than 1.5 mL and less than 5 mL. Samples above the expected volume may indicate an acute infection in the prostate or seminal vesicles, the glands responsible for producing semen. Samples below normal may indicate retrograde ejaculation, a chronic inflammatory process, or another obstruction in the seminal vesicles or prostate.

Concentration

Sperm concentration is currently measured with the aid of counting cameras that determine four concentration categories:

● Normozoospermia (normal sperm concentration) – more than 15 million sperm/mL;
● Oligozoospermia (low sperm concentration) – fewer than 15 million sperm/mL;
● Cryptozoospermia – absence of sperm in the initial sample, but sperm are found after centrifugation;
● Azoospermia – complete absence of sperm, even after centrifugation.
Motility

Motility is simply the ability of sperm cells to move through the medium, measured with the aid of specialized cameras. The sperm’s ability to progress toward the egg is essential for fertilization. According to this criterion, there are four types of sperm:

● TYPE A – motile sperm with rapid progressive movement;
● TYPE B – motile sperm with slow progressive movement;
● TYPE C – motile sperm without progression (they do not move forward);
● TYPE D – immotile sperm.

Semen considered normal by physicians is one that has Type A and B sperm totaling at least 32%, or alternatively, A+B+C totaling 40%.
Morphology

At this stage, the shape of the sperm cells is evaluated to determine whether their structure is suitable for fertilization. Sperm may have very large heads that prevent them from reaching the uterus, heads that are too small, causing disorganized movement, double tails, or even two heads, among other possible abnormalities. According to the World Health Organization (WHO), a healthy sample is one that contains at least 30% of sperm with normal morphology.

There is another technique used to evaluate sperm morphology known as Kruger Strict Morphology, developed by the South African scientist Thinus Kruger. Kruger Morphology assesses the reproductive cells by looking for abnormalities in the shape of the tail, head, or acrosome. The result is considered normal when the percentage of suitable gametes is equal to or greater than 4%.
Vitality

For samples in which more than 50% of the sperm are immotile, it is important to determine which are alive and which are dead. The vitality test provides this information with the aid of stains and microscopes (dead sperm absorb the stain because of their damaged membranes, while living sperm do not).
Cytological examination

This stage analyzes the other cells present in the semen sample, such as spermatogenic cells (sperm-producing cells), red blood cells, and even leukocytes (white blood cells).

Semen with a high concentration of white blood cells may indicate an infection caused by fungi or protozoa in the prostate or seminal vesicles.
Hypo-osmotic test

Finally, the integrity of the sperm cell membrane is evaluated using the hypo-osmotic test. Specialists believe that gametes with healthy cell membranes are more efficient at fertilizing the egg.

Origen Rio - Medicina Reprodutiva

Tests

SEMEN ANALYSIS

First evaluation (macroscopic): physical aspects of the semen

Color

Liquefaction

pH

Viscosity

Volume

Second evaluation (microscopic): condition of the sperm cells

Concentration

Motility

Morphology

Vitality

Cytological examination

Hypo-osmotic test

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