During a fertility consultation, the doctor often tests the semen. Routine semen tests include physical and biochemical indicators of semen, the quantity and quality of sperm, and the white blood cells in semen, which measure fertility and reflect the function of reproductive organs. However, it is not possible to send a random semen test to reflect the actual condition of the body; nor is it possible to conclude a disease or cause by the results of a single semen test. The reason is that there are many factors that can lead to errors in semen test results. It is related to the method, time, temperature, emotion and physical condition of the subject who retains semen. The correct way to collect semen is as follows: Semen collection should preferably be done in an outpatient clinic. The date of semen collection for testing should be within 5-7 days after the last ejaculation (including seminal emission and masturbation). Semen should be collected by the masturbation method. Interruption of intercourse is inappropriate because on the one hand, it may allow vaginal secretions to mix with semen and affect sperm motility and bacteriological examination; on the other hand, it may lose some of the first ejaculated semen. Ejaculation is a complex reflex process. For this reason, the whole process of ejaculation is divided into two stages: the sperm ejaculated in the first stage is much stronger than the sperm ejaculated in the second stage in terms of density, activity rate and survival rate. Therefore, when collecting semen, it is important to collect all the semen into a clean glass container and make sure not to lose the first part of the semen, but it does not matter if the last drop of semen is lost. Some people use condoms to collect semen, perhaps because they think it is more convenient, but in fact it is also very inappropriate. This is because condoms are rubber products and are also coated with lubricant, which can affect the performance of the sperm. The time and temperature of semen collection for testing should also be noted. The room temperature for semen collection should be in the range of 20-35 degrees Celsius, too low a temperature will result in a decrease in sperm survival. From the time of ejaculation, the semen should be delivered to the testing room within 15-20 minutes to begin testing. If more than 30 minutes have elapsed, it will have an impact on the accuracy of the liquefaction time of the semen and the accuracy of the sperm motility testing. This can make the test results meaningless. If the doctor thinks that the test result is suspicious and needs to be retested, or if the semen needs to be observed after treatment, the two semen tests should be performed 3 months apart. This is because the sperm production cycle is approximately 3 months.