The semen analysis is routinely ordered during the initial evaluation for the male partner.
To be valid the test needs to be performed at a competent laboratory. Non-specialized laboratories (such as Labcorp or Quest) perform semen analysis according to the World Health Organization (WHO) criteria, which will miss subtle but clinically significant sperm abnormalities. Most quality fertility centers employ the strict criteria (Kruger) to rigorously analyze the sperm structure (morphology). A complete semen analysis has the following parameters:
Volume – The normal semen volume is 2-4 ml. Low volume can result from dehydration or faulty collection technique. Persistent low volume (< 1 ml) can indicate retrograde ejaculation, a condition in which the semen flows backward into the bladder during ejaculation.
Concentration – The normal sperm concentration is 20 million per ml of semen. Concentration less than 10 million/ml usually requires in vitro fertilization (IVF) with sperm injection (ICSI). Sperm concentration is a critical factor.
Motility – At least 50% of sperm must be motile in order for the sample to be normal. However, progressive motility > 20% is usually sufficient for intrauterine insemination, provided that the sperm count is adequate. Progressive motility < 10% usually requires IVF with ICSI. Sperm motility is a critical factor.
Morphology – Using the Kruger strict criteria, the structure of the sperm can be rigorously evaluated. Normal semen has at least 4% of sperm with perfect morphology. Morphology values of 2%-3% are ‘subnormal’ but can still lead to pregnancy without requiring IVF. Morphology of 0-1% may require IVF/ICSI.
Progression – assesses the ability of sperm to move forward. Sperm have to move forward in order to reach the egg and to successfully penetrate the shell of the egg for fertilization. The grading system for progression varies among laboratories.
Direct anti-sperm antibody screen – checks for the presence of antibodies in the semen. Antibodies that attach to the tail can impair sperm motility while those bound to the head can prevent fertilization. The presence of significant anti-sperm antibodies usually means IVF and ICSI as treatment.