Semen collection, analysis and preparation: a mini review

Assisted reproductive techniques (ARTs) begin with spermatozoa processing, with the purpose to select the best spermatozoa for insemination. An appropriate semen analysis involves the evaluation of sperm concentration, motility and morphology. These parameters are still the mainstay in the assessment of male reproductive potentiality. The quality of semen sample influence directly the preparation method to perform. Different sperm separation approaches exist to maximize the yield of motile sperm. Sperm processing techniques should be gentle to avoid free radical formation. Moreover these procedures should prevent sperm damage, avoid non-physiological alterations, eliminate dead sperm and other cells or debris. The most common techniques used in andrology laboratories and ART programs are swimup, density gradient and simple washing. Generally, simple washing and swim-up procedures are favourite with good quality semen samples, whereas density gradient centrifugation is ideal with lower concentrated samples. Several efforts have been made to improve selection techniques. However methods recently proposed to further investigate the competence of spermatozoa are still not validated. To date, further randomized studies are needed before recommending these advanced sperm selection techniques in the clinical practice.