Semen analysis is a cornerstone of laboratory diagnostics in male reproductive health, offering insights into both sperm quality and the health of accessory glands like the seminal vesicles and prostate. Semen, a mixture of sperm and seminal fluid, is primarily composed of secretions from the seminal vesicles (60%-70%) and the prostate (20%-30%). Sperm, suspended in the seminal fluid, constitutes only 5%-10% of the total volume. This dual focus makes semen analysis essential for evaluating conditions such as seminal vesiculitis, prostatitis, and sperm-related fertility issues.
General Examination of Semen
Normal, liquefied semen typically appears homogeneous and grayish-white. In cases of low sperm concentration, the sample may appear more translucent. For patients with hematospermia (blood in semen), the appearance varies based on the amount of blood present, ranging from bright red to coffee-colored or dark red, sometimes with visible clots or microscopic red blood cells. In conditions like seminal vesiculitis or prostatitis, elevated white blood cell counts (>1.0×10⁶/ml) or significant bacterial growth in cultures may be observed. Additionally, tuberculosis or schistosomiasis can be detected through the presence of Mycobacterium tuberculosis or schistosome eggs, while suspected seminal vesicle cancer may reveal malignant cells in the semen.
Sperm Quality Assessment
Hematospermia, often linked to reproductive system inflammation, can adversely affect sperm quality, leading to reduced motility and abnormal morphology. For patients seeking fertility, a routine semen analysis is crucial to assess sperm health.
Sperm Concentration and Total Count
Sperm concentration refers to the number of sperm per milliliter of semen. According to the World Health Organization (WHO) Laboratory Manual for the Examination and Processing of Human Semen (5th edition), the lower reference limit for sperm concentration in adult males is 15×10⁶/ml. Values below this threshold indicate oligospermia, while the complete absence of sperm is termed azoospermia.
Sperm Motility
Sperm motility, a key factor in fertility, is categorized into three levels based on WHO guidelines: progressive motility (PR), non-progressive motility (NP), and immotility (IM). Progressive motility is particularly associated with successful conception.
Sperm Viability
Sperm viability, assessed through membrane integrity tests such as dye exclusion or hypo-osmotic swelling, measures the percentage of live sperm. The lower reference limit for viable sperm is 58%.
Sperm Morphology Evaluation
Sperm morphology is a critical indicator of male fertility. The WHO manual defines the lower reference limit for normal sperm morphology as 4%. Abnormalities are classified into four categories: head defects, neck and midpiece defects, principal piece defects, and excessive residual cytoplasm.
Leukocyte Assessment in Semen
Leukocytes, primarily polymorphonuclear neutrophils (PMNs), are commonly present in semen. Since peroxidase-positive granulocytes are the predominant type, peroxidase activity assays are useful for initial leukocyte screening. The WHO manual recommends a critical threshold of 1.0×10⁶/ml for peroxidase-positive cells, with total counts reflecting the severity of inflammation.
Conclusion
Semen analysis remains an indispensable tool in diagnosing and managing male reproductive health issues. By evaluating both sperm quality and the health of accessory glands, it provides critical insights for fertility assessment and the detection of underlying pathologies. Adherence to standardized protocols, such as those outlined in the WHO manual, ensures accurate and reliable results, guiding effective clinical interventions.
