To provide a correct result it is necessary to perform at least two, preferably three, separate seminal analyses with an interval between them of seven days to three months.

[1] The most common reasons for laboratory semen analysis in humans are as part of a couple's infertility investigation and after a vasectomy to verify that the procedure was successful.

At the laboratory level this is rare, as most healthcare providers will not test the semen and sperm unless specifically requested or there is a strong suspicion of a pathology in one of these areas discovered during the medical history or during the physical examination.

One source states that 30% of men with a normal semen analysis actually have abnormal sperm function.

[6] In NICE guidelines, mild male factor infertility is defined as when two or more semen analyses have one or more variables below the 5th percentile, and confers a chance of pregnancy occurring naturally through vaginal intercourse within two years similar to people with mild endometriosis.

The sample should never be obtained through coitus interruptus as some portion of the ejaculate could be lost, bacterial contamination could occur, or the acidic vaginal pH could be detrimental for sperm motility.

There are some situations that necessitate alternative collection methods, such as retrograde ejaculation, neurological injury or psychological inhibition.

[9] Others advocate obtaining a second semen analysis to verify the counts are not increasing (as can happen with re-canalization) and others still may perform a repeat vasectomy for this situation.

Chips for home use are emerging that can give an accurate estimation of sperm count after three samples taken on different days.

Such a chip may measure the concentration of sperm in a semen sample against a control liquid filled with polystyrene beads.

Normal sperm morphology is hard to classify because of lack of objectivity and variations in interpretation, for instance.

[14] A motile sperm organelle morphology examination (MSOME) is a particular morphologic investigation wherein an inverted light microscope equipped with high-power optics and enhanced by digital imaging is used to achieve a magnification above x6000, which is much higher than the magnification used habitually by embryologists in spermatozoa selection for intracytoplasmic sperm injection (x200 to x400).

[5] In clinical practice, a volume of less than 1,4 mL in the setting of infertility is most likely due to incomplete ejaculation or partial loss of sample, asides this, patient should be evaluated for hypoandrogenism and obstructions in some parts of the ejaculatory tract, azoospermia, given that it has been at least 48 hours since the last ejaculation to time of sample collection.

Men who are infected[18] with the human immunodeficiency virus (HIV) produce lower semen volume.

When there's no volume, the condition is named as aspermia, which could be caused by retrograde ejaculation, anatomical or neurological diseases or anti-hypertensive drugs.

[19] Presence of blood in semen (hematospermia) leads to a brownish or red coloured ejaculate.

Brown semen is mainly a result of infection and inflammation of the prostate gland, urethra, epididymis and seminal vesicles.

[citation needed] Other causes of unusual semen colour include sexually transmitted infections such as gonorrhea and chlamydia, genital surgery and injury to the male sex organs.

[5] A pH value outside of the normal range is harmful to sperm and can affect their ability to penetrate the egg.

[20] The liquefaction is the process when the gel formed by proteins from the seminal vesicles and the prostate is broken up and the semen becomes more liquid.

[11] MOT is a measure of how many million sperm cells per ml are highly motile, that is, approximately of grade a (>25 micrometer per 5 sek.

[23][24] Other techniques performed in order to measure the DNA fragmentation are: SCD (sperm chromatin dispersion test), ISNT (in situ nick translation), SCSA (sperm chromatin structural assay) and comet assay.

A high level of white blood cells in semen is called leucospermia and may indicate an infection.

[5] Apart from the semen quality itself, there are various methodological factors that may influence the results, giving rise to inter-method variation.

The site of semen collection does not affect the results of a semen analysis..[28] If produced at home the sample should be kept as close to body temperature as possible as exposure to cold or warm conditions can affect sperm motility Volume can be determined by measuring the weight of the sample container, knowing the mass of the empty container.

Sperm count can also be estimated by kits that measure the amount of a sperm-associated protein, and are suitable for home use.

Most systems are based on image analysis, but alternative methods exist such as tracking cell movement on a digitizing tablet.

[33] Raman spectroscopy has made progress in its ability to perform characterization, identification and localization of sperm nuclear DNA damage.

[34] Semen Fructose Test has made progress in its ability to perform characterization, identification and localization of sperm nuclear DNA damage.