What We Need to Know About the 3 Most Important Sperm Tests

We are living in an era where the science of human reproduction is evolving rapidly, and information regarding fertility testing and reproductive medicine procedures is now widely accessible to everyone. While this provides a significant advantage in terms of access to information, it can also become a source of anxiety and confusion, as the sheer volume of available data is often difficult for the recipient to interpret and understand due to its complexity and the conflicting information disseminated through various channels.

This article summarizes the most essential and scientifically validated information regarding the three most important diagnostic fertility tests for sperm. Accurate information on these topics helps us not only understand the utility of sperm testing but, more importantly, the significance of the results concerning male fertility and reproductive health

Semen Analysis 

• In semen analysis, the reference limits for sperm parameters are established by the World Health Organization (WHO, 2021) and are determined by the analysis of scientific metadata from men with successful natural conception within 12 months of initiating effort.
• The recommended WHO limits are indicative, and test results must be medically evaluated in conjunction with the clinical profile and medical history of the individual.

  Reference limits according to the World Health Organization (WHO, 2021)

• Fertility is a multifactorial and dynamic condition that can be affected by both simple and more complex factors, involving the reproductive potential of both sexes.
• Male infertility primarily manifests as isolated or combined disorders of sperm parameters regarding count (oligozoospermia), motility (asthenozoospermia), morphology (teratozoospermia), or the absence of spermatozoa in the ejaculate (azoospermia).
• Semen analysis results reflect the reproductive potential at the specific time of the examination; therefore, a single test is not an absolute indication of infertility.
• Measurements lower than the reference limits should not be perceived as a definitive sign of infertility, but rather as a need for further medical guidance.
• Male infertility is due to a wide range of known and unknown causes, which necessitates medical and diagnostic evaluation in cases where reduced values in sperm parameters are observed.
• Certain deviations from the reference limits are reversible, and improvement in sperm quality can be achieved, or other medical approaches may be recommended for male health and successful reproduction.

Semen Redox Potential or Oxidative Stress (sORP)

• The measurement of semen redox potential is a new method that detects potential imbalances in the production and inactivation of Reactive Oxygen Species (ROS) in the seminal fluid.
• Under normal conditions, ROS and antioxidants exist in equilibrium, as the body produces the necessary ROS for its proper function, while antioxidants neutralize excessive amounts to maintain homeostasis.
• This balance disruption can manifest as oxidative stress (>1.34) or reductive stress (<0.01). In these cases, either ROS appear in higher concentrations because they are not neutralized, or antioxidant factors inactivate more ROS than necessary for physiological balance.
• Disturbances in the Oxidation-Reduction Potential (ORP) can be attributed to various underlying endogenous or exogenous factors, such as age, lifestyle, radiation, chemical agents, environmental pollution, infections, inflammation, and various pathologies of the reproductive system, such as varicocele.
• Both conditions of equilibrium disruption are involved in the mechanisms that cause sperm DNA fragmentation, thereby affecting sperm quality and overall fertility.

Reference limits according to the most recent systematic reviews

Sperm DNA Fragmentation (DFI)

• During the final stages of spermatogenesis, each spermatozoon undergoes extensive molecular remodeling of its nucleus to compress and protect its genetic material.
• Failure of cellular mechanisms during sperm maturation, along with oxidative stress within the spermatogenesis environment, can cause breaks in one or both DNA strands, leading to chromosomal alterations and genomic instability.
• The integrity of sperm DNA is vital for reproduction and the development of healthy offspring, affecting both natural conception and assisted reproduction at almost all stages.
• A normal fragmentation rate in semen means that less than 15% of the spermatozoa in the sample carry fragmented genetic material. Furthermore, additional thresholds have been established; according to recent data, a limit of 20% appears safe for the reproductive outcome in Intrauterine Insemination (IUI) procedures, while this percentage increases to 25% for conventional In Vitro Fertilization (IVF) or Intracytoplasmic Sperm Injection (ICSI).

Specifically, it has been established that:

• There is a direct correlation between sperm DNA damage and male infertility.
• Elevated fragmentation levels (>20%) are predictive of male infertility.
• 1 in 4 men with unexplained infertility has a sperm DNA fragmentation rate higher than 20%.
• Men with oligoasthenoteratozoospermia exhibit significantly higher rates of DNA fragmentation.
• A normal semen analysis does not rule out the presence of oxidative stress or an elevated DNA fragmentation rate.

Increased sperm DNA fragmentation rates:

• Reduce the probability of natural conception.
• Decrease the likelihood of pregnancy and live birth through IUI procedures.
• Lower fertilization, implantation, and pregnancy rates, while negatively impacting embryo quality during IVF procedures.
• Negatively affect the quality of embryos derived from ICSI.
• Are associated with a higher risk of miscarriage or recurrent pregnancy loss, whether following natural conception or assisted reproduction (IVF and ICSI).

Can adversely affect embryonic development and the long-term health and well-being of the offspring.