Semen analysis is an important test in the evaluation of male infertility and is also used to confirm sterility after a vasectomy. A semen sample is examined for sperm concentration, morphology, motility, and semen biochemistry (e.g., pH level). Test results can include a number of pathologies, such as low sperm count (oligospermia) or complete lack of sperm in the ejaculate (azoospermia). However, semen analysis is not a definitive test for infertility and low sperm count does not necessarily rule out the ability to father children.
Indications for semen analysis
- Evaluation of male fertility (see also causes of male infertility)
- Confirmation of sterility after vasectomy
- The man is asked to abstain from sex/masturbation for 2–7 days before a semen sample is collected to maximize the quantity of the ejaculate and concentration of the sperm .
- Semen is collected after masturbation into a sterile container .
- Semen analysis should be performed within an hour of sample collection.
- Semen analysis should be repeated in 12-week intervals (minimum of 2 separate samples) .
|Volume||1.5 - 5 mL|
|Liquefaction||Complete within 30 minutes|
|Total number of sperm per ejaculate||> 39 million per ejaculate|
|Sperm concentration per mL||> 15 million per mL|
|Vitality (percentage of live sperm)||> 58% live sperm|
|Morphology (percentage of normal forms)||> 4% sperm are morphologically normal.|
|Total motility (progressive and non-progressive sperm)||> 40%|
|Progressive motility||> 32%|
|Fructose in seminal plasma||> 13 μmol/L|
|Leukocytes per mL of semen||< 1 million|
|Hypospermia||Low ejaculate volume (< 1.5 mL)|
|Azoospermia||No spermatozoa in the ejaculate|
|Cryptozoospermia||< 1 million spermatozoa/mL of ejaculate|
|Oligospermia||< 15 million spermatozoa/mL of ejaculate|
|Asthenozoospermia||< 32% of spermatozoa show progressive motility (category PR)|
|Teratozoospermia||Increased amorphous spermatozoa|
|Oligoasthenoteratozoospermia (OAT syndrome)||Low concentration, insufficient motility, and increased amorphous spermatozoa|
Specialized semen tests
Specialized semen tests are not routinely performed but can be necessary if semen analysis alone does not explain the cause of infertility.
- Semen culture: identification of bacterial infection if leukocytes are present in semen
- Sperm-cervical mucus interaction: detects anti-sperm antibodies
- Computer-aided sperm analysis: computer program that predicts the fertilizing capacity of sperm based on its motility
- Acrosome reaction: indicated for couples planning IVF