Body Fluids Semenial Fluid PP

Chapter 11: Semen

Learning Outcomes

Upon completing this chapter, the reader will be able to:

  • State the structures involved in sperm production and their function.
  • Describe the four components of semen with regard to source and function.
  • Explain the procedures for collecting and handling semen specimens.
  • Describe the normal appearance of semen and three abnormalities in appearance.
  • State two possible causes of low semen volume.
  • Discuss the significance of semen liquefaction and viscosity.
  • Calculate a sperm concentration and count when provided with the number of sperm counted, the dilution, the area of the counting chamber used, and the ejaculate volume.
  • Define round cells, and explain their significance.
  • State the two parameters considered when evaluating sperm motility.
  • Describe the appearance of normal sperm, including structures and their functions.
  • Differentiate between routine and strict criteria for evaluating sperm morphology.
  • Given an abnormal result in a routine semen analysis, determine additional tests that might be performed.
  • List two methods for identifying a questionable fluid as semen.

Purpose of Seminal Fluid Analysis

The analysis of seminal fluid serves several key purposes:

  • Evaluation of fertility of individuals.
  • Post-vasectomy semen analysis to confirm the absence of sperm.
  • Forensic analysis in cases such as potential sexual assault.

Semen Production

Structures and their Functions
  • Seminiferous Tubules of Testes: Site of spermatogenesis, where sperm cells are produced.
  • Epididymis: Location for sperm maturation.
  • Ductus Deferens: Responsible for propelling sperm to the ejaculatory ducts.
  • Seminal Vesicles: Provide nutrients for sperm and fluid, as well as enzymes and proteins critical for coagulation and liquefaction.
  • Prostate Gland: Adds alkaline mucus to neutralize acidic prostatic fluid and vaginal acidity.
  • Bulbourethral Glands: Contribute fluids that aid in the ejaculate.
Composition of Semen
  • Spermatozoa: 5%
  • Seminal fluid: 60%-70%
  • Prostate fluid: 20%-30%
  • Fluid from Bulbourethral glands: 5%

Types of Tests Requested in Semen Analysis

  • Volume & viscosity of the sample.
  • Appearance of the semen.
  • pH level of the semen.
  • Sperm concentration and total count.
  • Motility, including the quality of motility.
  • Morphology of sperm.
  • Viability of spermatozoa.
  • Presence of antisperm antibodies.

Specimen Collection Procedures

  • The semen specimen must be complete; the majority of sperm resides in the first part of the ejaculate.
  • Patients should follow detailed instructions:
      - Abstain from ejaculation for 2–3 days prior to collection, but no longer than 7 days.
      - Laboratories provide containers and ideally designate a room for specimen collection.
      - If collected at home, the specimen should be delivered to the laboratory within 1 hour and kept at room temperature.
  • Record both the time of collection and time of receipt by the laboratory.
  • A clotted specimen must liquefy in 30–60 minutes for proper analysis.
  • Use rubber or polyurethane condoms that are not lubricated or contain spermicide; specimens are considered biohazardous due to potential for hepatitis and HIV transmission.

Semen Appearance

  • Normal Semen: Gray-white color, translucent; characterized by a musty, bleach-like odor.
  • Abnormal Appearances:
      - White turbidity: indicative of infection, necessitating a culture.
      - Red coloration: suggests the presence of blood cells, which is considered abnormal.
      - Yellow color: may result from the presence of urine, prolonged abstinence, or medication effects; note that urine is toxic to sperm and can affect motility.
  • Clots not liquefied after 1 hour should be waited on before analysis.

Reference Values for Semen Analysis

The following are the reference values established for semen analyses:

  • Volume: 2-5 mL
  • Viscosity: Should pour in droplets within 60 minutes.
  • pH: 7.2–8.0
  • Sperm Concentration: Lower reference limit is >20 million/mL.
      - Count: Normal sperm count is >40 million/ejaculate.
      - Motility: >50% motility within 1 hour.
      - Vitality (% alive): Should be over 58% alive.
      - Morphology: >14% normal forms under strict criteria.
      - Round cells: <1.0 million/mL.

Semen Volume and Viscosity

  • Normal semen volume ranges from 2 – 5 mL,
  • Measured using a graduated cylinder, with decreased volume representing potential infertility or incomplete collection of the sample.
  • Normal viscosity is indicated by the formation of thin threads when withdrawing a sample using a pipette, with ratings from 0 (watery) to 4 (gel-like). High viscosity may impede sperm motility.

pH Levels of Semen

  • Normal pH range of semen is 7.2-8.0.
  • A pH level over 8.0 could indicate an infection, while a lower pH may indicate increased prostate fluid, obstruction of the ejaculatory tract, or poorly developed seminal vesicles.
  • pH can be checked using pH paper.

Sperm Motility

  • Adequate sperm motility is characterized by sperm demonstrating forward, progressive movement.
  • Samples should be examined within 1 hour of collection to accurately evaluate motility under conditions that minimize dilution and maintain viability by using a glass slide with a cover slip.
  • The percentage of sperm with progressive forward motion should be estimated over 20 fields or by counting 200 sperm to evaluate motility categories.
Grading Scale for Motility
  • 0: No movement
  • 1: No forward progression
  • 2: Slow forward movement, more lateral movement
  • 3: Slower speed, some lateral movement
  • 4: Rapid straight-line motility
  • Normal motility is rated >50%, with a criterion of >2 indicating fair quality of motility.

Sperm Concentration and Count

  • Sperm Concentration: Number of sperm per mL, with normal values between 20-250 million/mL, and borderline concentrations between 10-20 million/mL.
  • Sperm Count: Total number of sperm per ejaculate calculated as concentration multiplied by volume:
      - A normal count is >40 million/ejaculate.
  • Reference Range: 20-250 million/mL for concentration.
Counting Methodology
  • The Neubauer Chamber is often used, where a diluting fluid (usually sodium bicarbonate with formalin or tap water) immobilizes sperm; the dilution is 1 to 20.
  • Count the sperm in five small center squares, averaging the counts from both sides of the chamber while ensuring they agree within 10%.
  • An average count of 60 sperm leads to a concentration of 60,000,000 sperm/mL multiplied by 3 mL for a total sperm count of 180,000,000 sperm.
  • Sperm concentration must be multiplied by 1000 when using different square counts to ensure accuracy.

Sperm Morphology