WHO – 6th updated manual on semen examination

WHO – 6th updated manual on semen examination

Many couples all over the world are facing the problem of infertility and trying to find a solution. Semen analysis has been an important factor in evaluating male fertility. The World Health Organisation (WHO), vide their manuals on semen examination, has tried to regularise the process of semen examination and bring uniformity across the globe.

The previous manual (5th edition) on semen examination was published 11 years ago, in 2010. This year, 2021, the sixth updated manual has been released. In the decade that has passed between the issue of these 2 manuals, much progress has been achieved in the field which reflects in the new manual. At the same time, the editors have acknowledged that corrections have had to be made due to limitations in the previous manual. They have stated that semen examination cannot strictly differentiate between normal and pathological samples. They have acknowledged that semen analysis cannot be the only prediction of fertility. When the 5th manual was prepared, only 1,800 fertile men were tested to obtain the reference distributions for semen parameters. The lower 5th percentile was used to define these reference values. This caused controversy and the matter was disputed because, while it is commonly used to determine references in medical tests, it is not applicable to provide norms in semen analysis and is unable to discriminate between fertile and infertile patients. Hence, “normal” reference values in the 5th edition have been replaced by “decision limits” in the current 6th manual, under the classifications “normal”, “borderline” and “pathological”. Sperm concentration, morphology and motility now have different cut-off norms under these heads. This will help a great deal in arriving at conclusive decisions.

When the 5th manual was prepared, semen parameters were taken from various populations, but not from India. However, the 6th edition has included data from 5 more studies with 1,789 additional male subjects. The new studies have included data from Europe, Africa and Asia as well.

One commendation the WHO has earned is the inclusion of the Sperm DNA Fragmentation test in the 6th manual. As they explained, the SDF evaluation could be an important contribution to working on male infertility.

Another important factor the current manual includes is the importance of seminal oxidative stress and some methods for Reactive Oxygen Species (ROS) testing. Probably, due to limited availability of such testing, it appears under the “Advanced Examination” head. However, with recent proof of the impact of oxidative stress, with MOSI (male oxidative stress infertility) being a clinical entity, the relevance of ROS testing in semen analysis has been brought to light.

The WHO 6th manual has been streamlined to provide updated, evidence-based, quality control and standardized procedures and recommendations for scientists, technicians and laboratory managers to follow. Some old tests have been abandoned while additional new tests have been introduced. The importance of semen examinations cannot be denied and it is good to know that facilities are provided where these tests can be carried out carefully and accurately, to help with identifying and coping with male infertility.

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