Patient's question:
I'm newly married, and we've already started paying attention to the preparations before pregnancy. We want to get our bodies into the best condition before welcoming our little one, so we went for a physical check-up. Could you please tell me if the hospital offers routine semen analysis? What are the specific tests included in it?Doctor's answer:
Hello～Semen analysis is an important basis for assessing male fertility. Therefore, for men undergoing pre-pregnancy examinations or those diagnosed with male infertility, doctors first need to perform a semen analysis. The results of semen analysis are not only crucial for urologists but also for gynecologists. When the analysis confirms male infertility, it can avoid unnecessary and cumbersome tests for the wife and allow for timely treatment and preparation for pregnancy.Composition of Semen
Semen is a grayish-white liquid primarily composed of secretions from the testes, epididymis, prostate, and seminal vesicles, along with a small amount of secretion from the urethral glands. Sperm is the most important formed component of semen, accounting for 5–10%. Sperm develops from spermatogonia in the testes, with an entire developmental cycle of approximately 74 days. Adult males can produce about 100 million sperm daily. Changes in physical condition or external stimuli (e.g., radiation, temperature) can only affect sperm quality but not its developmental cycle.
The liquid component is called seminal plasma, which is the medium necessary for transporting sperm. Seminal vesicle fluid accounts for 60–70%, while prostatic fluid accounts for 20–30%.
Specific Examination Content of Semen Analysis
Collection of Semen Specimen
During semen analysis, the examinee must collect their own semen. Incorrect collection can affect the accuracy of the results. For semen collection, the examinee is required to abstain from ejaculation for 3–5 days. If the period is too short or too long, it will affect the test results. Semen should be collected using masturbation or coitus interruptus and stored in a clean container at a temperature close to body temperature (e.g., under close-fitting underwear) and delivered to the laboratory as soon as possible, no later than 1 hour. Condoms should not be used, as regular condoms contain spermicidal substances that can cause sperm death.
Routine Semen Analysis
Routine analysis is the most important part of semen testing and generally includes parameters such as semen color, volume, liquefaction time, sperm density, 1-hour survival rate, sperm motility, percentage of abnormal sperm, and white blood cell count.
Semen Color
Normal semen is transparent and grayish-white. If abstinence is prolonged, it may appear pale yellow. In cases of reproductive tract inflammation, it may turn yellow or even contain blood.
Semen Volume
The volume of each ejaculation is typically 2–6 mL but is influenced by ejaculation frequency and frequency. A volume of less than 1 mL per ejaculation is called oligospermia, while more than 6 mL is called hypersemia, both of which are abnormal conditions.
Liquefaction Time
Immediately after ejaculation, semen is gel-like and becomes liquid within 5–30 minutes. This process is called liquefaction. The liquefaction of semen requires the participation of a series of proteolytic enzymes. Thicker, non-liquefying semen is often seen in patients with prostatic or seminal vesicle diseases.
Semen pH
Semen is weakly alkaline, with a pH of 7.2–7.8.
Sperm Density
Sperm density refers to the number of sperm per milliliter of semen. A normal density is above 20 million sperm/mL. If it is below 20 million/mL, it is called oligospermia, which affects fertility.
1-Hour Survival Rate
The percentage of motile sperm within 1 hour after ejaculation should be ≥60%.
Sperm Motility
Sperm motility is classified into four grades:
- Grade A: Rapid linear forward movement
- Grade B: Slow forward movement
- Grade C: Local oscillation
- Grade D: Non-motile
Normal sperm motility is defined as A ≥25% or A+B ≥50%. If it is below normal, it is called asthenozoospermia. It is important to note that non-motile sperm does not necessarily mean they are dead; they may still be alive but have lost motility. Erythrosin staining is commonly used to determine if sperm are dead.
Percentage of Abnormal Sperm
Abnormal sperm refers to sperm with abnormal morphology, and their percentage should be below 30%. If the abnormal rate exceeds 30%, it is considered abnormal and may affect fertility.
White Blood Cell Count in Semen
The number of white blood cells in semen should be less than 5 per high-power field under normal conditions. If it exceeds 5, it may indicate reproductive tract inflammation.
Bacteriological Examination of Semen
When routine semen analysis shows abnormalities, doctors may recommend a bacteriological examination of semen. Infections in the male reproductive system can alter semen quality, such as volume, pH, liquefaction time, and sperm survival rate. Up to 30 types of pathogens, such as Staphylococcus, E. coli, Enterococcus, Mycoplasma, and Chlamydia, can cause infections. Semen infection may be a significant factor or cause of male infertility. Therefore, when semen analysis results are abnormal, a bacteriological examination is necessary to aid diagnosis and treatment. For bacteriological testing, the semen specimen should be collected in a sterile cup.
Biochemical Examination of Semen
In well-equipped hospitals, doctors may also request a biochemical examination of semen. Biochemical analysis of semen is a simple method to assess the secretory function of accessory glands. It includes fructose, zinc, acid phosphatase, and carnitine. Fructose primarily comes from seminal vesicle secretion and provides energy for sperm movement. Absence or reduced fructose is seen in congenital seminal vesicle absence or seminal vesitis, making it difficult to conceive. The prostate contains high concentrations of zinc and acid phosphatase, while the epididymis has high concentrations of carnitine, all of which are related to sperm function. Inflammation of the prostate or epididymis reduces their levels, affecting fertility.
Factors Affecting Semen Analysis
Semen analysis results may be influenced by factors such as:
- Too short or too long abstinence
- Recent physical fatigue
- Excessive alcohol and smoking
- Recent fever
- Partial leakage of semen during collection
- Poor collection environment
- Delay in sending the specimen after collection
These factors may lead to inaccurate results. Therefore, if a single test result is abnormal, it does not necessarily indicate a problem. Generally, 2–3 repeated tests should be conducted after an interval of 1–2 weeks. Only multiple abnormal results are clinically significant.
Judging Infertility Based on Semen Analysis Results
Based on the results of semen analysis, doctors can determine whether the examinee has infertility. According to semen analysis results, infertility can be classified as:
- Oligospermia: Sperm density below 20 million/mL
- Azoospermia: No sperm found after centrifugation and three examinations
- Asthenozoospermia: Low sperm motility
- Necrospermia: Most or all sperm in the semen are dead
- Non-liquefiable semen
Then, based on other examinations of infertility patients, such as physical and blood tests, to identify the exact cause or etiology of infertility (e.g., endocrine diseases, reproductive tract infections, positive antisperm antibodies, varicocele, sexual dysfunction), appropriate treatment measures can be taken to improve semen quality and restore fertility.
Treatment of Male Infertility
Currently, the treatment of male infertility mainly includes endocrine hormone therapy, antibiotic treatment to control reproductive tract inflammation, immunological infertility (positive antisperm antibodies) treatment, general treatment (vitamins, zinc, energy supplements), traditional Chinese medicine treatment, assisted reproductive technologies, and surgical treatment. All these treatments are based on the results of semen analysis.