Summary
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
Sample collection
- 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) .
References:[1][2]
Semen analysis
Semen analysis
| Characteristics | Normal findings |
|---|---|
| Volume | 1.5 - 5 mL |
| Color | Whitish, opalescent |
| Liquefaction | Complete within 30 minutes |
| pH | Basic 7.2–8.0 |
| 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 |
Pathological findings
| Conditions | Characteristics |
|---|---|
| Aspermia | No ejaculate |
| 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 |
References:[1][2][3]
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
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