Semen Analysis Parameters: What Is Normal and What Is Not?

When couples are having difficulty conceiving a child, both male and female factors affecting fertility must be evaluated. Semen analysis is a laboratory test that assesses sperm quality. Poor sperm quality is one cause of male infertility.

Key takeaways:
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    Semen analysis is a test used to look for causes of male infertility.
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    Semen analysis measures semen volume, sperm count, sperm concentration, sperm viability, sperm motility (movement), and sperm morphology (shape).
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    Low semen volume or low measures of sperm quality (sperm count, concentration, viability, motility, and morphology) can give clues about the causes of male infertility.

Semen analysis

Male factors affecting fertility include sperm quality and ejaculation problems, such as retrograde ejaculation. Semen analysis parameters are used to determine whether sperm and semen production is normal. Many factors can affect sperm production, including nutrition and hormone levels. Abnormal results on a semen analysis test do not identify the cause of the abnormality. However, when combined with other test results, abnormal results can point a doctor in the direction of the underlying problem.

How to prepare for semen analysis

To obtain the best possible semen sample, there are several steps you should take to prepare for a semen analysis and ensure that it provides accurate results. You should avoid sex and masturbation and abstain from ejaculating for two to seven days before collecting a sample. Do not use lubricants or saliva when collecting a sample; this can interfere with normal sperm function. Be sure to collect all of your semen in the provided container. You will likely need to collect another semen sample two weeks after the first sample.

What is normal?

Normal and abnormal are relative terms. When it comes to semen analysis there are no magic numbers that guarantee male fertility. However, guidelines published by the World Health Organization (WHO), based on research, list the ranges of each semen analysis parameter measured in studies involving thousands of fertile male participants. Measures that are below the lowest 5 percent are considered low; everything else can be considered normal. The following information is based on 2021 WHO guidelines. Low values are presented as a range.

Semen volume

Low semen volume is defined as less than 1.3 ml to 1.5 ml per ejaculate. The total amount of semen ejaculated at one time should be at least 1.5 ml. Poor production of sperm or seminal fluid can lower semen volume. Retrograde ejaculation into the bladder can also cause low semen volume.

Sperm count and sperm concentration

Sperm count is the total amount of sperm ejaculated, while sperm concentration is the number of sperm per volume of semen. A low sperm count is less than 35 to 40 million sperm per ejaculate; a low sperm concentration is less than 15 to 18 million sperm per milliliter of semen. Low sperm count or concentration can be caused by poor sperm production. Levels of testosterone and other sex hormones can help determine the cause of low sperm count or concentration.

Sperm vitality

Sperm vitality is a measure of how many live sperm are ejaculated. Normally, more than 50% to 56% of sperm in a sample are alive. Various problems can cause non-viable sperm production, including problems with the epididymis in the testes.

Sperm motility

Sperm motility is a measure of how well sperm can move. Normally, more than 29% to 31% of sperm show progressive motility (the ability to move forward). Total motility—which includes both progressive and non-progressive motility—should be more than 40% to 43%. Many factors can affect sperm motility, including hormones and medications.

Sperm morphology

Sperm with abnormal shape, or morphology, are unhealthy and may not function properly. At least 3.9% to 4% of sperm should have normal morphology; less than that indicates a problem with sperm production.

White blood cells

White blood cells (WBCs), also called leukocytes, are immune cells that exist throughout the body. High numbers of WBCs can be a sign of infection. More than 1 million WBCs per ml of semen is considered abnormal. This can be caused by infection of the testes, prostate, or urinary tract.

Other measures

Semen analysis also includes other measures that help assess semen quality, including pH and sperm agglutination. The pH of semen should be at least 7.2. Semen with a pH from 7.2 to 7.8 provides the best environment for sperm to be healthy and active. Semen analysis also looks for sperm agglutination, when sperm stick to one another and clump together. Sperm agglutination is abnormal.

Semen analysis is just one part of a complete workup to assess male infertility. Additional testing, including blood tests and imaging, may be needed to accurately diagnose infertility and determine the cause. Problems with semen or sperm quality found during semen analysis may reveal underlying medical conditions or health issues that are affecting fertility. In some cases, treating underlying conditions and improving health can improve fertility.

Many factors can affect sperm quality, including poor overall health, obesity, poor nutrition, medical conditions, and a wide variety of prescription medications. Fortunately, there are steps that many men can take to improve their sperm quality. If you have had a semen analysis test or one has been recommended, you should talk to your doctor and discuss what may be affecting your sperm quality and what you can do to improve your fertility.

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