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Semen analysis (sperm count test)

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Semen Analysis Overview

Semen analysis (also known as a sperm count test or spermiogram) is the cornerstone laboratory examination for evaluating male fertility status. It assesses the quantity and quality of both the seminal fluid (semen) and the sperm cells it contains, providing insights into spermatogenesis (sperm production) and the function of the accessory sex glands (prostate, seminal vesicles).

The analysis typically measures several macroscopic and microscopic parameters, which are compared against established reference values, such as those published by the World Health Organization (WHO), to determine potential fertility issues.

Preparation and Collection

Obtaining accurate and reliable semen analysis results requires strict adherence to collection guidelines:

  • Sexual Abstinence Period: A period of 2 to 7 days (optimally 3-4 days) of sexual abstinence (no ejaculation) is required before collection. Shorter or longer periods can affect sperm concentration, volume, and motility. Consistency in abstinence period is important for follow-up tests.
  • Substance Abstinence: Avoid alcohol (including beer) and potentially potent medications (like certain sedatives or hypnotics, check with your doctor) during the abstinence period.
  • Avoid Heat Exposure: Refrain from using saunas, hot tubs, or prolonged exposure to high heat for several days (ideally 2-7 days) before collection, as heat can negatively impact sperm production and motility.
  • Collection Method: The preferred method is masturbation into a clean, sterile, wide-mouthed container provided by the laboratory. The entire ejaculate must be collected. Collection via coitus interruptus or standard condoms is generally unacceptable (condoms often contain spermicides). Special non-toxic collection condoms may be available.
  • Timing and Transport: The sample should ideally be collected at the laboratory or delivered within 30-60 minutes of collection. It must be kept close to body temperature (e.g., carried in an inside pocket) during transport and protected from extreme temperatures.

Failure to follow these conditions can significantly affect results, potentially leading to an incorrect diagnosis.

Parameters Measured (WHO Standards & Interpretation)

The following table outlines key semen parameters, their reference values (primarily based on WHO 5th Edition, 2010 lower reference limits, though the original text refers to the 4th edition), and common interpretations of deviations. Note that results are always evaluated comprehensively, considering all parameters together.

Semen Analysis Parameters (Based on WHO 5th Ed. Lower Reference Limits)
Parameter
WHO Lower Limit (5th Ed.)
Interpretation Notes
Abstinence Period 2-7 days Essential for comparing results to reference values. Consistency crucial for repeat tests.
Volume ≥ 1.5 mL Low volume (hypospermia, <1.5 mL) may indicate issues with seminal vesicles, prostate, ejaculatory duct obstruction, or collection problems. No upper limit defined by WHO.
Color Characteristic grey-opalescent Red/brown suggests blood (hematospermia) - check for tumors, stones, trauma, infection. Yellow may indicate jaundice, vitamins, urine contamination, or long abstinence. Very clear may mean low sperm count.
pH ≥ 7.2 Reflects balance between alkaline seminal vesicle fluid and acidic prostate fluid. Low pH may suggest ejaculatory duct obstruction or seminal vesicle issues. High pH (>8.0) may indicate infection.
Liquefaction Time Complete within 60 min Semen initially coagulates then liquefies via prostate enzymes (like PSA). Delayed liquefaction (>60 min) may indicate prostate dysfunction or enzyme deficiency, hindering sperm motility assessment.
Viscosity Forms discrete drops (thread length < 2 cm) Assessed after liquefaction. Increased viscosity (hyperviscosity - thread > 2 cm) can impair sperm motility. Often associated with prostate or seminal vesicle inflammation (vesiculitis) or dysfunction.
Sperm Concentration
(Density)		 ≥ 15 million/mL Low count (<15 million/mL) is oligozoospermia. Absence of sperm is azoospermia. High count (>250 million/mL) is polyzoospermia. Causes include endocrine disorders, varicocele, infections, genetic factors, toxins, radiation. No upper limit defined by WHO.
Total Sperm Count
(per ejaculate)		 ≥ 39 million Calculated as Concentration x Volume. Reflects overall sperm production. Reasons for low count similar to low concentration.
Sperm Motility
(within 60 min)		 ≥ 40% total motility (Progressive + Non-Progressive)
OR
≥ 32% progressive motility (PR)		 Reduced motility is asthenozoospermia. Assesses ability to move forward. Categories: PR (Progressive - actively moving linearly or in large circles), NP (Non-Progressive - moving but not progressing, e.g., small circles, tail flicking), IM (Immotile). Causes include varicocele, infection, antisperm antibodies, structural defects, prolonged abstinence, environmental factors (heat), toxins.
Sperm Morphology
(Normal Forms)		 ≥ 4% (using strict Kruger criteria) Assesses the percentage of sperm with normal shape (head, midpiece, tail). Low percentage (<4% strict) is teratozoospermia. Often associated with varicocele, infections, toxins, genetic factors. Poor morphology can impair fertilization. (Note: Original text value of >15% likely refers to older, less strict criteria).
Sperm Vitality
(Live Sperm)		 ≥ 58% Assesses percentage of live sperm (using staining or hypo-osmotic swelling test). Important if motility is low. High percentage of dead sperm (>42%) is necrozoospermia. Causes can include epididymal pathology, antisperm antibodies, infection, toxins, prolonged abstinence, spinal cord injury.
White Blood Cells (WBCs)
(Leukocytes)		 < 1 million/mL Increased WBCs (>1 million/mL) is leukocytospermia (or pyospermia). Indicates inflammation or infection in the male reproductive tract (e.g., prostatitis, epididymitis, vesiculitis, urethritis). Requires specific staining (e.g., peroxidase) to differentiate from immature germ cells.
Red Blood Cells (RBCs)
(Erythrocytes)		 Should be absent or very rare Presence of significant RBCs (hematospermia) requires investigation. Causes include infection/inflammation, trauma, tumors, stones, vascular abnormalities, recent procedures (biopsy).
Immature Germ Cells
(Spermatogenesis cells)		 Usually < 5 million/mL (No formal % standard) Presence is normal, but significantly increased numbers may indicate testicular dysfunction or damage (e.g., impaired maturation, post-chemo/radiation, varicocele). Need to distinguish from WBCs.
Sperm Agglutination Absent or minimal Clumping of motile sperm (head-to-head, tail-to-tail, etc.). Suggests presence of anti-sperm antibodies (immunological infertility). Must distinguish from non-specific aggregation (sperm clumping with mucus/debris).
Mucus Minimal / No standard Small amounts may be normal. Excessive mucus can increase viscosity and indicate inflammation of accessory glands.
Lecithin Bodies
(Lecithin Granules)		 No standard Small granules originating from the prostate. Abundant in normal semen. Reduced numbers suggest decreased prostatic function (e.g., due to chronic prostatitis). Often assessed qualitatively ("few", "moderate", "many").
Amyloid Bodies
(Corpora Amylacea)		 No standard Small, laminated bodies, also from the prostate, more common in older men. Presence/absence noted qualitatively; significance debated, but absence might suggest reduced prostate function.

General Interpretation Notes

  • Semen parameters can fluctuate significantly even within the same individual. A single abnormal result should generally be confirmed with one or two repeat analyses after 1-3 months.
  • Results are compared to WHO reference limits, which represent the 5th percentile of men who achieved pregnancy within 12 months – values below these limits do not necessarily mean infertility but indicate reduced likelihood.
  • Interpretation must consider all parameters together and the patient's clinical history.
  • The terms ending in "-zoospermia" describe sperm parameters (oligo-, astheno-, terato-, azo-, necro-), while "-spermia" describes ejaculate characteristics (hypo-, hyper-, aspermia [no ejaculate], pyo-, hemato-).

References

  1. World Health Organization (WHO). (2010). *WHO laboratory manual for the examination and processing of human semen* (5th ed.). WHO Press. (Provides standard procedures and reference values).
  2. Cooper, T. G., Noonan, E., von Eckardstein, S., Auger, J., Baker, H. W., Behre, H. M., ... & Vogelsong, K. M. (2010). World Health Organization reference values for human semen characteristics. *Human Reproduction Update*, 16(3), 231–245. https://doi.org/10.1093/humupd/dmp048
  3. American Urological Association (AUA). (n.d.). Evaluation of the Infertile Male. Retrieved from https://www.auanet.org/guidelines/guidelines/male-infertility
  4. Mayo Clinic Staff. (n.d.). Semen analysis. Mayo Clinic Patient Care & Health Information. Retrieved from https://www.mayoclinic.org/tests-procedures/semen-analysis/about/pac-20394929
  5. Lab Tests Online. (n.d.). Semen Analysis. Retrieved from https://labtestsonline.org/tests/semen-analysis