Diagnostics
Sperm Function Test Kits
The semen analysis is one of the most basic laboratory test for clinical assessment of the infertile couple. Routine semen analysis comprising of parameters like semen count, motility and morphology give fairly good idea of efficiency of spermatogenesis and fertilization ability of sperm. But in many circumstances this data is insufficient to explain cause of infertility and test for functional potential of sperm are necessary. These specialized tests provide valuable diagnostic information not available by routine tests and are useful in such cases.
We are introducing some of the kits to test functional potential of sperm. |
Seminal plasma Fructose Test |
Fructose is a marker for seminal vesicle function. Its function in the seminal plasma is as a substrate for the glycolytic (Anaerobic) metabolism of the spermatozoa. This is an important energy source for the sperm and exclusion of the seminal vesicular component from the ejaculate will result in almost completely immotile sperm.
Fructose levels in semen are androgen dependent. Fructose is secreted by seminal vesicles.
Fructose levels should be determined in any patient with azoospermia and especially in those whose ejaculate volume is less than 1 ml, suggesting seminal obstruction or atresia or ejaculatory tract duct obstruction. Absence of fructose, low semen volume, and failure of the semen to coagulate indicate either congenital absence of the vas deference and seminal vesicles or obstruction of the ejaculatory duct. Disorders of the seminal vesicles and a subsequent reduction in the fructose concentration in semen will also result in a reduced motility of sperm. As the seminal vesicles contribute more than half of the total volume of semen, absence of seminal vesicular secretions will reduce semen volume. Thus the measurement of fructose concentration in men with low volume ejaculates may be of great value diagnostically.
Another situation where fructose estimates are helpful is in men with polyzoospermia and low motility. Occasionally in men with very high sperm concentrations (more than 350 million sperm per ml), the sperm are immotile due to relative deficiency of fructose. If this semen picture is present, the diagnosis can be confirmed by finding very low concentrations or even absence of fructose in semen.
The Hypo-Osmotic Swelling Test
The HOS test is based on the ability of live spermatozoa to withstand moderate hypo-osmotic stress. Dead spermatozoa whose plasma membranes are no longer intact plasma membranes have no osmoregulatory mechanism active and show uncontrolled swelling resulting in the rupture of their over distended plasma membranes.
The spermatozoa that show controlled swelling under test conditions is considered the good fraction with low osmotic fragility.
Leukocyte Screening Test
Most of the human ejaculates contain leukocytes and other round cells. Predominant cell types are neutrophils and immature spermatids and spermatogonia. It is therefore necessary to differentiate types of cells as excessive presence of neutrophils may indicate the existence of reproductive tract infection. Presence of immature spermatids and spermatogonia denote problems in spermatogenesis.
Furthermore, leukocytospermia may be associated with defects in the semen profile, including reductions in the volume of ejaculate, sperm concentration, and sperm motility as well as loss of sperm function as a result of oxidative stress, and/or secretion of cytotoxic cytokines. It is difficult to define threshold concentration of leukocytes beyond which fertility will be impaired. The impact of these cells depends upon the site at which leukocytes enter the semen, the type of leukocytes involved and their state of activation.
As a general rule a normal ejaculate should not contain more that 5X106 round cells/ml, while the number of leukocytes should not exceed 1X106 /ml. When the semen contains more than 1X106 /ml leukocytes, microbial tests should be performed to investigate if there is a accessory gland infection.
Sperm Vitality Staining
The sperm vitality is reflected in the proportion of spermatozoa that are “alive”. It is measured by assessing the ability of sperm plasma memberane to exclude extra-cellular substances like dyes. Sperm vitality should be determined in semen samples with less than fifty percent motile spermatozoa. Vitality assessment also provides check on the accuracy of motility assessments; as the percentage of live spermatozoa should slightly exceed the total percentage of motile spermatozoa. Eosin-Nigrosin staining is used fort assessing vitality. The technique is based on the principle of dead cells will take up the eosin, and as a result stain pink. The Nigrosin provides a dark background, which makes it easier to assess the slides.
