The World Health Organisation (WHO) has published several editions of the “Manual for the Examination of Human Semen and Sperm-Cervical Mucus Interaction”, the last one in 2010. Those manuals help and guide andrology laboratories to determine sperm quality. Moreover, in recent years, the European Society for Human Reproduction and Embriology (ESHRE) in collaboration with the WHO have developed a program to improve standardization between laboratories in terms of sperm sample diagnosis and assessment criteria.
There are many parameters obtained through a spermiogram, the most frequently studied are:
- Liquefaction: After the ejaculation, the sperm sample is coagulated and needs to be liquefied in order to perform any tests. In normal conditions the sperm is totally liquefied in 60 minutes after the ejaculation
- Viscosity: When the sperm sample is very viscous it may be a sign of a prostatic dysfunction.
- Volume: The normal volume of an ejaculate sample after 3 or 5 days of sexual abstinence is 1.5 ml approximately. Lower volumes might suggest hypospermia.
- Color: Sperm is usually opalescent white, lightly yellow. When the color is altered, it is recommended to study possible causes.
- pH: Values should be greater than 7.1. Lower values might be a sign of azoospermia (lack of spermatozoa) or chronic inflammatory processes.
- Sperm concentration: Normal values are around 15 million per ml ejaculated or 39 million per complete semen sample. When these values are lower it could indicate Oligozoospermia.
- Motility: The percentage of motile spermatozoa and progressively motile is analyzed. The progressive motility value should be over 32%, on the contrary it might indicate Astenozoospermia.
- Vitality: The percentage of vital spermatozoa must be over 58%. Lower values could indicate Astenoozoospermia.
- Morphology: There might be 4% or more normal spermatozoa in an usual spermiogram. Lower percentages could indicate Teratozoospermia.
- Leukocytes: When the leukocyte concentration is over 1 million per ml of sample it might indicate an infection (leukocytosis).
- Antisperm Antibodies or Mar test: The number of spermatozoa with adherent particles or cells is reflected. More than 50% spermatozoa clustered together suggests an immunological problem.
The concept of “Lower Reference Limit (LRL) was established in the last manual of the WHO.
If values are over the limit do not guarantee a successful fertilization or an on-going pregnancy, but it does increase possibilities. The LRL has progressively been reduced due to social behaviors and new life habits as food, tobacco, environmental toxics, etc. The reference values established in the 4th manual edition of the WHO compared with those in the 5th and last edition are shown in the board below:
|4th edition (1999)||5th edition* (2010)|
|Liquefaction||Complete in 60min||Complete in 60min|
|Color||Opalescent white||Opalescent white|
|Concentration (ml)||20 million||15 million|
|Leukocytes (ml)||< 1million||< 1 million|
|<50% sperm with bound particles||<50% sperm with bound particles|
* Values of Lower Reference Limit (LRL) currently used in Specialized Fertility Centres.
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