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Urinalysis & Body Fluids

Physical Testing

Now that we have a pristine semen sample in the lab, collected and handled according to our strict protocols, the analysis begins. And it begins not with a microscope or a complex analyzer, but with our own eyes, a timer, and a pipette

The physical, or macroscopic, examination of semen is a fundamental and diagnostically rich process. Do not underestimate its importance. These simple observations are a direct reflection of the functional status of the accessory glands - the prostate and the seminal vesicles. A failure in this initial examination can often pinpoint the source of a man’s infertility before we even look for a single sperm. Every parameter we measure is guided by the World Health Organization (WHO) manual, which provides the global standard for semen analysis

1. Liquefaction & Viscosity: The Great Escape

This is the very first assessment we perform after the specimen arrives and is placed in the 37°C incubator. These two parameters are physiologically linked but measured sequentially. They tell the story of the semen’s transformation from a protective gel to a fluid medium that allows for sperm motility

  • Physiology Recap
    • Coagulation (Step 1): Immediately upon ejaculation, fibrinogen-like proteins from the seminal vesicles cause the semen to form a gel-like coagulum
    • Liquefaction (Step 2): Over the next 15-60 minutes, powerful proteolytic enzymes from the prostate gland, primarily Prostate-Specific Antigen (PSA), break down this coagulum, turning the gel into a liquid
  • Methodology
    1. Liquefaction
      • The time of collection is noted. The sample is placed in a 37°C incubator
      • At regular intervals (e.g., every 15 minutes), the sample is gently swirled or tilted
      • We record the time at which the entire specimen has liquefied (i.e., it is no longer a gel but a homogenous, watery fluid)
    2. Viscosity (Post-Liquefaction)
      • After liquefaction is complete, we assess the viscosity
      • A clean pipette or glass rod is introduced into the sample and then withdrawn
      • We observe the thread that forms from the pipette tip
  • Interpretation & Clinical Significance
    • Normal Liquefaction: The specimen should completely liquefy within 60 minutes at 37°C. Most normal samples liquefy within 15-30 minutes
    • Normal Viscosity: The fluid should form small, discrete droplets that fall from the pipette tip. A thread, if it forms, should be less than 2 cm long.
    • Abnormal: Incomplete or Delayed Liquefaction (> 60 minutes)
      • This is a significant finding that points directly to a prostatic dysfunction.: It indicates a deficiency in the necessary proteolytic enzymes (like PSA)
      • The specimen remains a gel. This is a clinically important cause of infertility, as sperm are trapped within the coagulum and are unable to move
    • Abnormal: Hyperviscosity (Thread > 2 cm)
      • This indicates the sample has liquefied but remains abnormally thick or “stringy.”
      • It can be due to prostatic issues or inflammation/infection of the accessory glands
      • Like incomplete liquefaction, hyperviscosity mechanically impedes sperm motility. It also makes accurate microscopic analysis (sperm counting and motility assessment) extremely difficult. If a sample is hyperviscous, it may need to be treated with an enzyme like chymotrypsin before analysis can proceed

2. Volume: A Measure of Glandular Output

Once the sample is fully liquefied, we can accurately measure its volume. This is a simple measurement that reflects the secretory capacity of the glands

  • Physiology Recap: Volume is a composite fluid: ~60-70% from the seminal vesicles, ~20-30% from the prostate, and ~5% from the bulbourethral glands

  • Methodology

    • The entire volume is poured into a clean, graduated cylinder or measured using a wide-bore serological pipette
    • The volume is recorded to the nearest 0.1 mL

  • Interpretation & Clinical Significance

    • Normal Volume (WHO): ≥ 1.5 mL
    • Aspermia: No ejaculate volume. This indicates a serious problem like anorgasmia or complete retrograde ejaculation
    • Hypospermia (Low Volume, < 1.5 mL): This is a common and important finding. The causes, in order of likelihood, are:
      1. Pre-analytical Error: Incomplete collection (patient missed part of the sample) or a short abstinence period. This is the most common reason and must be ruled out first
      2. Ejaculatory Duct Obstruction: A blockage preventing the bulk of the fluid from the seminal vesicles from being released
      3. Congenital Absence of the Seminal Vesicles: A rare genetic condition where the primary fluid-producing glands are missing
      4. Retrograde Ejaculation: Semen is ejaculated backwards into the bladder instead of out the urethra
    • Hyperspermia (High Volume, > 5.0 mL): This is less common and usually clinically insignificant, often associated with prolonged abstinence

3. pH: The Acid-Base Balance

The pH of semen is a delicate balance between the acidic secretions of the prostate and the alkaline secretions of the seminal vesicles

  • Methodology
    • After liquefaction, a drop of the well-mixed fluid is placed onto a pH test strip (range 6.0-10.0)
    • The color is compared to the chart, and the pH is recorded
  • Interpretation & Clinical Significance
    • Normal pH (WHO): ≥ 7.2: (Typically 7.2 - 8.0)
    • Abnormal: Acidic pH (< 7.2)
      • This is a highly significant finding, especially when combined with other parameters
      • It indicates a relative surplus of acidic prostatic fluid and a lack of the buffering alkaline fluid from the seminal vesicles
      • The classic triad of low volume, acidic pH, and azoospermia (no sperm): is strongly suggestive of either ejaculatory duct obstruction or the congenital bilateral absence of the vas deferens (and seminal vesicles).
    • Abnormal: Alkaline pH (> 8.0)
      • This usually suggests an infection: within the reproductive tract. Bacteria can produce alkaline byproducts, raising the pH. It is often accompanied by an increased WBC count on the microscopic exam

4. Appearance: Color & Clarity

This is a simple visual inspection against a white background

  • Interpretation & Clinical Significance
    • Normal: Homogenous, gray-white, and opalescent. The opacity is due to the high concentration of sperm and prostatic fluid
    • Less Opaque / Clearer: This often correlates with a low sperm concentration. A very clear sample may be azoospermic
    • Red or Brown (Hematospermia): Indicates the presence of blood (RBCs). This can be caused by infection, inflammation, or, rarely, malignancy of the GU tract
    • Yellow: Can be due to several factors
      1. Urine Contamination: This is the most serious cause. Urine is spermicidal. The specimen will often have a characteristic urine odor and poor/absent sperm motility
      2. Prolonged Abstinence: Old sperm can cause a yellowish tinge
      3. Jaundice: or taking certain vitamins
    • Greenish Tinge: Suggestive of a prostatic or other GU tract infection

Conclusion

As you can see, before we even look at a single sperm, we have gathered a wealth of diagnostic information. We know if the prostate is producing its liquefying enzymes. We know if the seminal vesicles are contributing their proper volume and alkaline fluid. We have clues about potential obstructions, infections, or contamination. This physical examination is the essential first chapter in the story of a patient’s fertility, and it masterfully sets the stage for the microscopic analysis to come