Diagnostic Assessment Flashcards
What is the point of semen analysis? (5)
- Analysis of seminal fluid and sperm parameters = indicator of male fertility potential.
- Usually 1st diagnostic step in male fertility investigations.
- Remains the gold standard.
- WHO criteria for normal semen parameters (2021).
-via manual semen analysis or computer assisted semen analysis (CASA)
When does normal liquefaction take place?
20-30mins post production.
What does an abnormally long liquefaction time indicate?
An infection e.g. bacterial prostatitis
Sperm Volume can be assessed via 2 methods (2)
1) direct volume measurement: Volume (ml) measured directly using serological pipette
2) Volume from weight: Weighing sample pots before + after sample production (difference = sample volume) -> studies on human semen have shown weight to be an accurate index of vol.
Sperm concentration (Density) (3)
Sperm conc. = quantity of sperm present in a sample
measured in millions per ml
determined using as counting chamber
What diagnosis is given if the sperm conc. is below the ref. value in density testing?
Oligozoospermia
when should sperm motility be tested? (2)
ASAP after liquefaction of the sample, within 1 hour following ejaculation
= to limit the deleterious effects of dehydration, pH or changes in temperature on motility.
How do you test for sperm motility? (5)
- Mix the semen sample well.
- Remove aliquots of semen immediately after mixing (~10μl each), allowing no time for the spermatozoa to settle out of suspension.
- Make a wet preparation approximately 20μm deep (2 replicates). Wait for the sample to stop drifting (within 60 seconds).
- Examine the slide with phase-contrast optics at ×200 or ×400 magnification. Assess approximately 200 spermatozoa per replicate for the percentage of different motile categories.
- Compare the replicate values to check if they are acceptably close. If so, proceed with calculations; if not, prepare new samples.
4 categories of sperm motility (5)
Sperm motility is classed into 4 categories based on current WHO (2021) criteria:
- Rapidly progressive motility (a): spermatozoa moving actively, either linearly or in a large circle, covering a distance, from the starting point to the end point, of at least 25 μm (or ½ tail length) in one second.
- Slowly progressive motility (b): spermatozoa moving actively, either linearly or in a large circle, covering a distance, from the starting point to the end point, of 5 to < 25 μm (or at least one head length to less than ½ tail length) in one second
- Non-progressive motility (c): all other patterns of motility with an absence of progression, e.g. swimming in small circles, the flagellar force hardly displacing the head, or when only a flagellar beat can be observed.
- Immotility (d): no movement.
WHO Ref Values
* a+b≥30%
* a+b+c≥42%
What diagnosis is given if the sperm motility is below the ref. value?
Asthenozoospermia
Standardising sperm motility (2)
- Count only spermatozoa with intact head and tail.
- Evaluate at least 200 spermatozoa in a total of at least 5 fields per replicate. Avoid repeatedly viewing the same field
how is Sperm Morphology assessed? (3)
- Assessed directly on the wet preparation
- Using stains (Papanicolaou staining, Diff-QuikTM staining, Shorr stain)
Sperm is smeared on slides and fixed before the staining protocol of choice is applied.
Normal Sperm head morphology (4)
- Smooth, regularly contoured and generally oval in shape.
- Well-defined acrosomal region comprising 40–70% of the head area.
- Acrosomal region should contain no large vacuoles, and not more than two small vacuoles, which should not occupy more than 20% of the sperm head.
- The post-acrosomal region should not contain any vacuoles.
Normal Sperm tail morphology (4)
- Slender, regular midpiece about the same length as the sperm head.
- The major axis of the midpiece should be aligned with the major axis of the sperm head.
- Residual cytoplasm is considered an anomaly only when in excess i.e. when it exceeds one third of the sperm head size.
- The principal piece should be thinner than the midpiece and around 10 times the head length. It may be looped back on itself provided there is no
sharp angle indicative of a flagellar break.
Sperm Vitality - when is it tested? (3)
Determined by assessing the membrane integrity of the spermatozoa - esp
important for samples w/ low progressive motility.
- Assessed ASAP after liquefaction of the semen sample, preferably at
30 minutes, but no later than 1 hour post-ejaculation. - No. of spermatozoa with intact membrane expressed as % live spermatozoa.
