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Ten tips on semen analysis

Reports from andrology labs can often be confusing. Urologist Mr Suks Minhas offers 10 pointers on getting the most from them.

1. Ask the patient to produce two samples, the second a month or two after the first.

Semen analysis is the cornerstone in the assessment of infertile men but results can vary quite considerably from month to month. It is important to ask the patient to produce two samples, ideally to be analysed by the same laboratory, especially if the first is abnormal.

2. A pregnancy can still occur if semen parameters are ‘subnormal' on the WHO scale or even in the pathological range.

Below are the normal ranges for semen analysis based on the WHO minimum standard:

• Volume of ejaculate:2.0 ml or more

• pH: 7.2-8.0

• Sperm concentration:20 million/ml or more

• Motility: 50% or more with forward progression

• Morphology: 15% or more with normal forms

• Vitality: 75% or more live

• White blood cells: fewer than 1 million per ml

3. Provide patients with clear instructions on how to collect and deliver a specimen. This can often be surprisingly difficult. Specific instructions should include:

• Ideally, astain from sex for three days beforehand, but not more than seven.

• Produce a sample by masturbation, into a sterile container.

• The whole sample should be collected.

• The lid of the container should be kept on until the last moment to prevent bacterial contamination.

• Ensure that the laboratory gets the sample within one hour.

• The patient should keep the sample warm inside his clothing (25-37°C), until it is delivered.

4. The most common abnormality seen is oligoasthenoteratozoospermia (OATs), a term describing low count, poor motility and shape.

Some of the causes of OATs are:

• idiopathic (30% of all infertile men)

• cryptorchidism

• varicoceles

• drugs and gonadotoxins

• chemotherapy

• radiotherapy

• genito-urinary infection

• endocrinopathy

• partial ejaculatory-duct obstruction

• unilateral vasal obstruction

• reduced spermatogenesis

• genetic.

5. Terms used in describing semen parameters are:

• Azoospermia – the patient produces semen containing no sperm.

• Oligozoospermia – the concentration is low, less than 20 million/ml.

• Asthenozoospermia – less than 50% are active.

• Teratozoospermia – more than 85% are abnormally shaped

• OATS – fewer than 20 million/ml with less than 50% being motile and more than 85% abnormally shaped.

• Necrospermia – all sperm are dead.

• Pyospermia or leucospermia – presence of a large number of white blood cells in the semen, often associated with an infection.

5. The main causes of azoospermia are sample error, testicular failure, obstruction or endocrine causes.

In cases of ejaculatory-duct obstruction and congenital absence of the vas deferens, the semen usually is acidic, low volume with low fructose. Remember that most of the ejaculatory volume comes from the prostate and seminal vesicles. Only 1% is derived from the testicles. So in cases of testicular obstruction or testicular failure, these parameters are usually normal.

6. The macrosopic appearance of the seminal fluid can be helpful in detecting pathologies and should be reported along with the counts and morphology.

• Appearance: a normal semen sample has a grey/yellow appearance and is opalescent. A deeper yellow colour may indicate the presence of leucocytes and a brownish tinge may indicate the presence of blood (haemospermia).

• Volume: after two to three days' abstinence there should be more than 2ml of semen, although men who masturbate a sample often produce lower volumes than during sex. To determine if this is pathological, the volume has to be placed in context of the other parameters such as pH and the presence of fructose.

• Liquefaction: when semen is ejaculated it coagulates on contact with the air, then, over about 20 minutes, it liquefies. Liquefaction should be complete at the time of testing – one hour after ejaculation.

• Viscosity: this is a measure of the fluid nature of the sample. Semen should have a fairly watery consistency at the time of testing.

• Agglutination: this refers to the presence of motile sperm ‘stuck' together and may indicate the presence of antibodies.

• pH: the normal pH of semen is 7.2-8.0 – pH of semen decreases with time but should not be less than 7.2 at one hour.

7. There are many causes of the presence of auto-antibodies, although treatment is limited.

Auto-antibodies cause agglutination of sperm. This can clearly have an impact on the fertilising potential. There are number of causes, including:

• acquired or congenital ductal obstruction (unilateral or bilateral)

• vasectomy

• testicular/epididymal infections

• testicular torsion/trauma

• cryptorchidism

• varicoceles.

8. If semen analysis demonstrates azoospermia it is worthwhile repeating the sample at a laboratory where they centrifuge the sample.

Often in azoospermic patients the only treatment available will be a testicular exploration with a view to biopsy and a sperm retrieval (see point 9 below). But small quantities of sperm can be found after centrifuging, and if they are present this will change treatment.

In vitro fertilisation or intracytoplasmic sperm injection using ejaculated sperm may be an option as opposed to surgical intervention.

9. The fact that sperm is not present does not mean there is no hope for the patient.

Sperm can be retrieved directly from the testicle by surgical means. Sperm can be directly separated from testicular tissue. Even in men with testicular failure who are azoospermic, sperm can be retrieved in up to 60% of cases.

10. Refer all men with abnormal semen parameters for urological assessment. It is often tempting to refer couples for IVF treatment.

In most cases this will be the correct management for the patient. However, it is important to note that a number of urological conditions can lead to abnormalities in semen parameters.

Mr Suks Minhas is a consultant urologist and andrologist and honorary senior lecturer at the Institute of Urology and University College Hospital, London.

Competing interests None declared

Human spermatozoa fertilising an ovum Semen analysis


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