Want more "standardization" of semen analysis results?
by Leo Vankrieken, Eur. Eng.
International Marketing Manager
Reproductive Endocrinology

Semen Analysis Parameters

Microscopic semen analysis is a time-consuming and arduous task for even the most skilled technologist. Automated systems have made the analytical component faster, less labor intensive and more objective. Of the current technologies—primarily semen quality analyzers using electro-optics, and computer-assisted semen analysis—electro-optics is proving more user friendly and cost effective for routine screening of semen quality in the assessment of male infertility.

Semen analysis is a critical element in the investigation of male infertility, along with hormonal testing, medical history and a physical examination to rule out any sexual or ejaculatory dysfunction. Although the occurrence of infertility in men has often been underestimated, just as many cases involve a clinical problem with the male as with the female (Table 1).

Table 1. Breakdown of clinically diagnosed infertility cases by gender.¹

Diagnosing male infertility
Semen analysis is used to determine whether spermatozoa quality is adequate to fertilize an oocyte. The following terms have been adopted to describe male fertility/infertility status:

	Normozoospermia: normal ejaculate
	Oligozoospermia: sperm concentration less than the reference value
	Asthenozoospermia: motility value less than the reference value
	Teratozoospermia: percentage of spermatozoa with normal morphology less than standard value
	Oligoasthenoteratozoospermia: disturbance of all three variables sperm concentration, motility and morphology
	Azoospermia: no spermatozoa in the ejaculate, occurring in approximately 10 to 20 percent of men receiving care in infertility centers
	Aspermia: no ejaculate.

In certain irreversible cases, in vitro fertilization (IVF) and related technologies, such as intracytoplasmic sperm injection (ICSI), can still make it possible for some men to father biological children. Adjunctive hormone, enzyme, nutritional and chromosomal testing, along with visual and functional assessments, can assist in determining the cause and appropriate therapeutic interventions.

Various technologies
Microscopic analysis has been the primary method of evaluating semen since the 1920s. It provides a sperm count and classifies motility and morphology. This method has several drawbacks: it is tedious, labor intensive, has poor reproducibility and is highly subjective, the accuracy of results being dependent on several factors including the expertise of the technologist.

Although computer-assisted semen analysis (CASA) systems were introduced into the market in the 1980s, they are found mainly in universities, research laboratories and sophisticated IVF centers. CASA systems primarily report motility and provide a more detailed classification and analysis once a determination of infertility has been established. The cost, labor-intensive sample processing, skill required for operation and limited menu have restricted the adoption of CASA systems for routine semen analysis.

In the 1990s, Medical Electronic Systems Ltd. (MES; Caesarea, Israel) introduced the first line of automated semen analyzers for routine screening of male infertility. The latest model, the SQA-V, distributed by DPC under the brand name SPERMALITE^TM, provides a basic screening analysis of concentration, motility and morphology in 75 seconds. This automated system uses electro-optics to transmit light through the specimen to the photodetectors that measure the patterns of light emitted. Variations in the light beams are detected, digitized and routed to an internal computer. The computer analyzes the data through the application of specially derived algorithms, and results are reported in a form that complies with WHO and Kruger* criteria.

Also available with the SPERMALITE system is the V-Sperm video-enhanced visualization software, which allows for enhanced direct visualization (1000 x magnification) of samples contained either in the self-aspirating capillary or in conventional microscope slides. The visualization system serves as a complementary tool to view atypical cases, identify specific pathologies, and enable more detailed manual sperm morphology assessment when required. With the aid of an external video card, video clips (MPEG files) and images may be stored on an external PC and added to patient reports. The enhanced data management, data analysis, graphs and image processing provide operators expanded system operation.

The SPERMALITE provides routine laboratories with a quick, reproducible and accurate means of evaluating semen samples, without painstaking manual analysis. It also requires minimal skill to operate and virtually no sample preparation. The addition of the SPERMALITE to DPC's line of reproductive products is just another demonstration of the Company's commitment to provide its customers with more comprehensive solutions for all their testing needs.

The SPERMALITE SQA-V provides laboratories with a quick, reproducible and accurate means of screening semen samples.

*Available outside the US

Common Semen Analysis Parameters

A basic semen analysis evaluates the number of spermatozoa (per volume and per ejaculate), motility and morphology.

Concentration is the number of sperm per milliliter of seminal fluid; the sperm count is the total number of sperm per ejaculate, calculated as the product of sperm concentration and ejaculate volume.1 Average sperm concentration is normally more than 60 million per milliliter, while a concentration of less than 20 million per milliliter is considered subfertile.

Motility is the ratio of the number of moving sperm to the total number of sperm (in a given volume), expressed as a percentage. Sperm motility is assessed by categorization into any of four groups:

Rapid progressive: a
Slow progressive: b
Nonprogressive: c
Immotile: d.

There should be more than 40 million sperm in the ejaculate. The World Health Organization (WHO) reference values state that 50% or more of the sperm should be motile (grades a + b + c) or 25% or more should exhibit progressive motility (grade a + b).²

Morphology refers to the shape and appearance of spermatozoa, taking into account whether or not the sperm head, neck, midpiece and tail are free of defects. During analysis, sperm are characterized according to specific sets of criteria, the most common being the WHO and Kruger morphology standards. The WHO has not established a reference value for the percentage of sperm that should be free of morphological defects, but data suggest that the fertilization rate in vitro decreases as normal morphology falls below 15 percent.¹

Other common parameters evaluated in a semen analysis include volume, pH, white blood cell count, presence of antisperm antibodies, color, viscosity, agglutination, aggregation and time until liquefaction.

References
1. Jeyendran RS. Interpretation of semen analysis results: a practical guide. Cambridge, UK: Cambridge University Press, 2000.

2. World Health Organization. WHO laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 4th ed. Cambridge, UK: Cambridge University Press, 2000.