Components of a Semen Analysis
A standard semen analysis includes evaluation of volume, pH, sperm concentration, total sperm number, vitality, progressive motility, total motility, and morphology, all of which are essential for comprehensive assessment of male fertility potential. 1
Standard Parameters and Reference Values
- Volume: Lower reference limit of 1.4 mL (range 1.3-1.5 mL). Low volume (<1.4 mL) with acidic pH suggests ejaculatory duct obstruction or absence of seminal vesicles 1
- pH: Should be greater than 7.2; acidic pH (<7.0) with low volume suggests distal obstruction in the genital tract 2, 1
- Sperm concentration: Lower reference limit of 16 million/mL (range 15-18 million/mL) 1
- Total sperm number: Lower reference limit of 39 million per ejaculate (range 35-40 million) 1
- Vitality: Lower reference limit of 54% live spermatozoa (range 50-56%) 1
- Progressive motility: Lower reference limit of 30% (range 29-31%) 1
- Total motility: Lower reference limit of 42% (range 40-43%) 1
- Morphology: Lower reference limit of 4.0% morphologically normal forms (range 3.9-4.0%) 1
Collection and Handling Requirements
- Patients should abstain from sexual activity for 2-3 days before collection 1
- Collection methods include masturbation or intercourse using specialized semen collection condoms 1
- Specimens should be kept at room or body temperature if collected at home 1
- Examination should occur within one hour of collection to ensure accurate assessment of motility 1
Clinical Terminology and Interpretations
- Aspermia: Complete absence of semen in ejaculate 2
- Azoospermia: Absence of spermatozoa in the semen, requiring centrifugation of the sample to confirm 2
- Oligozoospermia: Low sperm concentration 2
- Asthenozoospermia: Reduced sperm motility 2
- Teratozoospermia: Abnormal sperm morphology 2
- Normozoospermia: Normal semen parameters 2
- Retrograde ejaculation: Semen flows backward into the bladder; post-ejaculatory urinalysis should be performed if ejaculate volume is less than 1 mL 2, 1
Additional Testing When Abnormalities Are Found
- For azoospermia, laboratories should centrifuge the ejaculate and examine the pellet for rare sperm 2
- Karyotype testing is recommended for males with primary infertility and azoospermia or sperm concentration <5 million/mL when accompanied by elevated FSH or testicular atrophy 2, 3
- Y-chromosome microdeletion testing should be considered for severely oligospermic males (found in 5% of males with sperm concentrations 0-1 million) 2, 3
- Fructose testing can help identify seminal vesicle dysfunction or ejaculatory duct obstruction 1
- Sperm antibody testing may be performed for suspected immunological infertility 1
Quality Control and Frequency of Testing
- A single properly performed semen analysis is often sufficient for initial evaluation 1
- If abnormalities are detected, a second confirmatory analysis should be performed at least one month after the first 1, 3
- Standardized procedures and quality control are essential for accurate results 4
Common Pitfalls to Avoid
- Inadequate abstinence period can significantly affect volume and concentration 1
- Improper collection technique can invalidate results 1
- Delayed analysis negatively impacts motility assessment 1
- Failure to follow standardized procedures leads to high variability between laboratories 1
- Over-reliance on a single parameter rather than considering the entire profile 1
Evolution of Semen Analysis Techniques
- Basic subjective estimation of sperm parameters has been largely replaced by more objective and advanced methods 5
- Computer-assisted semen analysis (CASA) provides automated assessment of sperm concentration, motility, and motion characteristics 6
- Standardized laboratory procedures with quality control and quality assurance are fundamental for accurate semen analysis 4