• Clinical science

Semen analysis

Abstract

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

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

  • Not routinely performed
  • Additional testing if semen analysis 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
last updated 12/27/2017
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