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Urinalysis & Body Fluids

Collection & Handling

We have just reviewed the complex physiology of semen production. Now, we must turn our attention to what is unequivocally the most critical phase of semen analysis: the pre-analytical process of sample collection and handling

This cannot be overstated. An immaculately performed analysis on a poorly collected or improperly handled specimen will yield results that are not just useless, but dangerously misleading. A patient could be misdiagnosed as infertile, or a man who has had a vasectomy could be incorrectly told he is sterile, with potentially life-altering consequences

Unlike blood or urine, a semen sample cannot be casually obtained. The collection process itself is a variable that we must control as rigidly as possible. As laboratory scientists, we are responsible for providing crystal clear, unambiguous instructions to the patient and then meticulously documenting the handling of the specimen from the moment it arrives at the laboratory window

Patient Instructions: Setting the Stage for an Accurate Result

The quality of the sample is determined long before the patient even arrives at the lab. The instructions we provide are paramount

1. Abstinence Period: The Critical Balance

  • Requirement: The World Health Organization (WHO) mandates a period of sexual abstinence for a minimum of 2 days (48 hours) and a maximum of 7 days.
  • Physiology and Rationale
    • Too Short (< 2 days): Sperm are stored in the epididymis. If ejaculation occurs too frequently, the epididymal reserves will be depleted. This will result in a specimen with a falsely low volume and a falsely low sperm concentration.
    • Too Long (> 7 days): Sperm that are stored for too long in the epididymis begin to senesce and die. While the volume and concentration may be high, a large proportion of the sperm will be non-motile or dead, leading to a falsely low motility result
  • Lab Action: The patient must report the exact abstinence period (in days). This information is a required part of the semen analysis report. If the period is outside the 2-7 day window, the result must be interpreted with caution, and a note recommending a repeat collection should be added

2. Collection Method: Ensuring a Complete & Clean Sample

  • Ideal Method: Masturbation. This is the WHO-recommended method as it ensures the collection of a complete, uncontaminated specimen
  • Specimen Container: The sample must be collected directly into a sterile, wide-mouthed container provided by the laboratory
    • Why sterile?: To prevent bacterial contamination that could affect sperm viability and pH
    • Why wide-mouthed?: To ensure the entire ejaculate is collected
    • Why lab-provided?: To ensure the container is made of a non-spermicidal material. Many plastics and lubricants are toxic to sperm
  • The Critical Importance of a COMPLETE Collection
    • Semen is ejaculated in a specific sequence. The first portion: of the ejaculate is rich in sperm from the epididymis and the enzyme-rich fluid from the prostate. The last portion consists mainly of the fructose-rich fluid from the seminal vesicles that makes up the bulk of the volume
    • If the first portion is lost: The sperm concentration will be falsely low, and the pH may be abnormally alkaline
    • If the last portion is lost: The semen volume will be falsely low, the sperm concentration will appear falsely high, and the sample may not coagulate properly
  • Lab Action: The patient must report if any portion of the sample was lost or spilled. This must be documented on the report, as it can invalidate the entire analysis

3. Prohibited Methods

  • Coitus Interruptus (Withdrawal): Unacceptable. The first, sperm-rich fraction is almost always lost, and the sample will be contaminated with vaginal cells and bacteria
  • Ordinary Condoms: Unacceptable. Most commercially available condoms contain spermicidal agents or lubricants that will kill the sperm and invalidate the motility assessment
  • Exception: Special, non-toxic silicone condoms (e.g., a Male-Factor Pak) can be used in cases where masturbation is not possible for personal or religious reasons

Transport & Handling: The Race Against Time

Once collected, the specimen begins to degrade immediately. Time and temperature are our greatest enemies

1. Time from Collection to Analysis

  • Requirement: The specimen must be delivered to the laboratory within 1 hour of collection
  • Rationale: Motility is the most time-sensitive parameter. Sperm motility begins to decline significantly after 60 minutes at room temperature. A delay in delivery will lead to a falsely low motility result
  • Lab Action
    • The patient must: record the exact time of collection on the container or requisition form
    • The laboratory must: record the exact time of receipt
    • The “time to analysis” must be documented. If analysis begins >60 minutes after collection, the motility result must be interpreted with extreme caution and a comment must be added to the report

2. Temperature During Transport

  • Requirement: The specimen must be maintained at ambient or body temperature (20°C to 37°C) during transport
  • Rationale: Sperm are extremely sensitive to temperature shock
    • Too Cold (< 20°C): Cold shock will irreversibly immobilize the sperm, causing a falsely low motility.
    • Too Hot (> 40°C): Excessive heat will also kill sperm
  • Practical Instructions: The patient should be instructed to transport the specimen in an inside pocket, close to their body, to maintain a stable temperature. They should never leave it in a car on a hot or cold day

3. Laboratory Receipt: The First Steps

  1. Verify Information: Confirm all patient identifiers, the collection time, and the abstinence period. Ask the patient directly if the collection was complete
  2. Record Receipt Time: Immediately log the specimen into the LIS
  3. Place in Incubator: Immediately place the specimen in a 37°C incubator. This maintains the optimal temperature for sperm viability and, critically, facilitates the next essential physiological step: liquefaction

Summary: The Pre-Analytical Checklist

For every semen sample you receive, you must be able to mentally check off these boxes. A “no” to any of these questions compromises the integrity of the sample

  • Abstinence: Is it between 2 and 7 days?
  • Collection Method: Was it masturbation into a proper container?
  • Completeness: Was the entire sample collected?
  • Time: Will the analysis begin within 60 minutes of collection?
  • Temperature: Was the sample protected from cold or heat shock?

Conclusion

The pre-analytical phase of semen analysis is not a prelude to the test; it is part of the test. It is an active process of patient education, controlled collection, and meticulous documentation. A failure at any step in this chain of custody and handling can lead to a diagnostic error with profound personal consequences for the patient. By mastering and enforcing these stringent requirements, we ensure that the numbers we generate in the laboratory are a true and accurate reflection of the patient’s reproductive health