Having children is undoubtedly a very important event for a family. About 85% of married couples who do not use contraception and have a regular sex life will become pregnant within a year, while about 12-15% of couples suffer from infertility, of which male factors account for about 50%. However, many patients do not have a minimum understanding of infertility, or spend a long time moving from one hospital to another to receive unreasonable treatment, such as requesting medication based on the results of a semen analysis, requesting assisted reproduction (IVF) without any treatment, or receiving treatment not for the cause of infertility, but for the cause of infertility. This shows that not only the patients lack knowledge, but also some doctors are wrong about the treatment of male infertility. Whenever I see such patients, I always think of writing some scientific articles to help patients raise their awareness of male infertility and guide them to the right hospital and doctor, but I have been too busy with other things to realize this plan. A week ago, I received an appointment from a staff member who said that although there are many popular articles on the internet related to male infertility, the most important concerns of patients have not been well answered, so I hope to write a popular article on this subject to help patients learn to see a doctor. Therefore, I intend to put aside my other work for the time being and write a series of popular articles on male infertility, so that patients suffering from infertility will take fewer detours, get the right treatment in time and save on medical expenses. This series of popular science articles includes what precautions to take before semen examination, how many times a semen examination needs to be done, how patients can read the semen analysis report, what further tests need to be done if the semen analysis is abnormal, what diseases affect male fertility, which diseases need medication or surgery, and under what circumstances assisted reproductive technology (IVF) needs to be chosen. We hope that patients who read the first article will continue to wait and find the next one. In this article, the content to be introduced to you is the precautions related to semen examination, and in the next article, we are going to introduce how to read and understand the semen analysis report. 1.What is semen analysis? What tests are included? Semen analysis refers to the examination of the patient’s semen from the appearance and microscopic examination of a series of indicators, which is the most basic and primary examination item to evaluate male infertility. The test indicators include semen volume, semen appearance, liquefaction degree, total sperm count, sperm density, sperm vitality, sperm survival rate, sperm morphology and so on. 2.What do patients need to pay attention to before the semen analysis test? (1) Abstinence time should be kept at 3~5 days. The length of abstinence before semen discharge can cause significant changes in semen volume and sperm density, affecting the results of semen examination. The number of sperm increases slowly after 4 days, and the sperm density decreases when it exceeds 7 days, and the number of dead sperm and abnormal sperm may appear after long-term abstinence. The number of dead sperm and abnormal sperm may increase after prolonged abstinence. Therefore, abstinence for 3 to 5 days is generally recommended for semen examination. The World Health Organization (WHO) recommends abstinence for 2 to 7 days. Abstinence for shorter than 2 days or longer than 7 days has a greater impact on semen quality and is generally not used. (2) Collect all semen intact when taking semen. When semen is ejaculated, the initial front semen discharge is clear and sticky, mainly playing the role of lubricating the urethra to facilitate ejaculation, with very little sperm content; the second discharge is the main part of the ejaculation, with the highest number and quality of sperm; the last ejaculation is the rear semen discharge, with very little sperm and low quality of fertilization. Therefore, when masturbating to take semen, you need to align the semen collection container and collect all the semen intact. (3) Is it possible to collect semen at home and send it to the hospital later? Under normal circumstances, semen liquefaction takes 15-20 minutes after semen discharge. The composition and pH of the liquefied semen will change over time, and leaving semen for a long time will inevitably lead to sperm viability being affected, so semen analysis should be performed within 1 hour after semen is obtained, and should not exceed 2 hours when semen is incompletely liquefied or not liquefied at all. In addition, both semen liquefaction and sperm viability are affected by temperature. Therefore, semen should be collected near the examination room in the hospital. If the patient cannot adapt and cannot take semen in the hospital, semen can be collected at home or in a hotel near the hospital, etc. However, semen should be sent to the examination room in the hospital within 30 minutes after removal, and the specimen should be kept close to the body to keep warm at 25~37° if it is a cold day. 3.How many times do I need to do semen examination in total? How long is the interval between each test? What if the semen test results are bad or good? Semen examination should be performed 2~3 times at 2~3 weeks interval, and the abstinence time before each semen collection must be consistent. Parameters such as semen volume, sperm density and sperm vitality are affected by various factors such as usual health level, good or bad rest, and alcohol consumption. Therefore, it is possible that the results of each semen analysis may be different, or even vary greatly. Therefore, an evaluation cannot be made with the results of one semen analysis, and two to three semen examinations need to be performed at intervals of 2 to 3 weeks, which can provide an appropriate evaluation of the basic function of sperm production. In order to accurately compare different semen specimens from the same patient, the duration of abstinence before semen collection must be consistent. In patients with large differences in semen parameters, follow-up examinations should be performed over a period of 2 to 3 months.