Semen Analysis

Fertility & Conception

Key Points

Semen analysis is the first test men do for fertility investigations.
It gives indication of volume, quantity of sperm, motility and morphology.

What is Sperm Analysis?

Basic semen analysis is the first test most men have for fertility investigations. The test analyses semen - the fluid containing sperm (plus a few other substances) that’s released during ejaculation.

A semen analysis measures three major factors of sperm health:

the number of sperm
the shape of the sperm
the movement of the sperm

How is Semen collected?

Your doctor will let you know what you should do in preparation for the semen analysis. To get the best sample:

Avoid ejaculation for 24 to 72 hours before the test.
Avoid alcohol, caffeine, and drugs two to five days before the test.
Avoid any hormone medications as instructed by your doctor.

There are four main ways to collect a semen sample:

Masturbation: the preferred way to get a clean sample.
sex with a condom
sex with withdrawal before ejaculation
ejaculation stimulated by electricity

Interpreting Semen Analysis

According to the World Health Organization 2010 guidelines, a normal semen sample will have the same or better than:

Volume

Normal value: minimum 1.5 millilitres of fluid

Low semen volume can be caused by:

an obstruction of the vas deferens (the duct that carries sperm from the testicles to the urethra)
absence or blockage of the seminal vesicle
partial retrograde ejaculation
or a hormonal imbalance

Total Sperm Count

The total number of sperm found in the provided semen sample.

Normal Value: About 39 x 10^6 sperm per ejaculate is considered the lower acceptable limit.

Having a lower than normal count of sperm is sometimes called oligospermia.

Azoospermia is when no sperm cells are found.

Sperm Concentration

Sperm concentration is the number of sperm found in one millilitre of semen.

Normal Value: at least 15 x 10^6 sperm per millimetre.
Low sperm concentration may be part of an overall low sperm count. It could also be related to an abnormally high ejaculate volume.

Vitality (Viability)

Sperm viability refers to the percentage of live sperm in the semen sample.
The test uses a special stain that will only enter the sperm if they have damaged membranes (the outer part of the sperm). If stain enters them, they are classed as dead. This is only usually performed if there is evidence that a large proportion of sperm are not moving from the motility assessment.

Normal Value: at least 58% of the sperm cells should be viable.

If results are abnormal, it is called Necrozoospermia.

Motility (movement)

Motility is reported as a percentage (%). It describes how the sperm are moving. They are categorised into four groups depending on speed and direction:

Rapid progressive sperm: move forward very quickly.
Sluggish progressive sperm move forward but slower.
Non-progressive sperm move in circles/on the spot.
Immotile sperm do not move at all.

Normal Value: more than 40% of sperm must move normally an hour after ejaculation. And at least 32% should swim in a forward movement or in large circles.

If results are abnormal, it is called Asthenozoospermia (poor sperm motility).

Morphology Shape

It refers to the shape of the sperm cells. The head, midsection, and tail are evaluated, as well as the measurements and proportions between each.

Normal Values: at least 4% should have a normal shape.

If results are abnormal, it is called Teratozoospermia.

Liquefaction

When semen is ejaculated, it is thick and gelatinous, to help adhere to the cervix. The semen eventually liquefies to enable the sperm to swim better.

Normal Value: Semen should liquefy within 20 to 30 minutes of ejaculation.

If there is delayed liquefaction, there may be a problem with the prostate, the seminal vesicles, or the bulbourethral glands

pH

Semen pH is a measurement of how acidic or alkaline the semen is. The seminal vesicle fluid should be more alkaline, while the prostate fluids should be more acidic. In combination, they balance each other out in the semen. Semen that is too acidic may kill the sperm or prevent fertilization.

Normal Values: The semen should have a pH greater than 7.2. Currently, there's no consensus on how more alkaline semen may affect fertility, and so there's no upper pH limit according to the WHO guidelines.