Semen analysis: Introduction, Physical, chemical, microscopic examination, normal range of sperm count and clinical significance
Introduction of Semen analysis
Semen is a grey opalescent fluid that forms at ejaculation. It consists of a suspension of spermatozoa in seminal plasma. Semen analysis uses to check the reproductive status of a person. It is necessary to note the following points while reporting for routine semen examination.
- Abstinence days (Obtain the semen analysis at least 3 days of abstinence from coitus)
- Method of sample collection
- Time and place of sample collection
Collection and examination time is also necessary for semen analysis. Semen should examine within 30 minutes.
Physical examination
Colour and appearance: Greyish-white, viscid, opaque (normal finding)
Clinical significance
Increased turbidity may associate with inflammatory processes in some parts of the reproductive tract.
Viscosity: The specimen of normal viscosity can be poured drop by drop.
Clinical significance
Increased viscosity is concerned with the poor invasion of the cervical mucus in post-coital studies. Absence of viscosity points to reduced cell content.
Volume: 2-5 ml (normal finding)
Clinical significance
A lesser amount may arouse suspicion of deficiency and premature weakening by vaginal acidity.
Liquefaction time: 20-30 minutes (normal finding)
Clinical significance
Failure to liquefy within 30 minutes may associate with infertility. The semen from males with bilateral congenital absence of the vas deferens and seminal vesicles fails to coagulate due to the absence of coagulation substrate.
Chemical examination
pH: 7.2-7.8 (normal finding)
Clinical significance
pH values less than 7.0 are frequently associated with semen consisting largely of prostate secretions due to congenital aplasia of the vasdeferens and seminal vesicles.
Fructose: 150-300 mg/dl (normal finding)
Clinical significance
Disorders of seminal vesicles may lead to reduction in fructose concentration. There is an inverse relationship between fructose level and sperm count. High fructose values associated with low sperm count.
Microscopic examinations
Sperm count: 40-300 millions/ml (normal value)
Clinical significance
The complete absence of spermatozoa is called azoospermia. A reduced number is termed oligozoospermia.
related clinical conditions:
mumps, orchitis, prostatitis, occlusion or absence of efferent ducts, hypopituitarism, hypogonadotropic hypogonadism. The sperm count may be low in estrogen secreting tumors and in hypo-and hyperthyroidism.
Motility after 2 hours, 3 hours, and 6 hours: 60-95% (normal finding)
Clinical significance
Motile forms decrease by about 5% per hour after the fourth hour following collection. Motility less than 60% may be associated with infertility.
Abnormal forms: 0-20%
Clinical significance
More than 20% of abnormal forms may be associated with infertility.
Following abnormalities in spermatozoa are observed.
Heads: too small, too large, double heads, pointed heads, ragged heads
Middle piece: absent, bifurcated, or swollen.
Tails: double, curved, rudimentary, or absent
pus cells: 1-2/ HPF (normal finding)
Clinical significance
Increased number of pus cells-Inflammation due to infection in some parts of the reproductive system. Infection of the seminal vesicle.
Epithelial cells: 1-2/HPF (normal finding)
Clinical significance
Increased number: not significant
Red blood cells: Absent (normal finding)
Clinical Significance
Tuberculosis of seminal vesicle, rupture of the blood vessel, infection of the prostate, vitamin C deficiency.
Trichomonas: Absent (normal finding)
Clinical significance
Trichomonas infection i.e. motile flagellate with pus cells
References
- Textbook of Medical Laboratory Technology
by Praful B. Godkar, Darshan P. Godkar - Textbook of Medical Laboratory Technology by Ramnik Sood (2006)
- https://www.healthline.com/health/semen-analysis
- https://www.webmd.com/infertility-and-reproduction/guide/what-is-semen analysis
- https://www.medicalnewstoday.com/articles/323736#why-is-sperm-analysis-done
- https://medlineplus.gov/lab-tests/semen-analysis/
- https://www.who.int/docs/defaultsource/srhrdocuments/infertilityexamination-and-processing-of-human-semen-5ed-eng.pdf sfvrsn=5227886e_2