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Understanding Semen Analysis Results

What's Normal, What's Abnormal, and Why

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Updated July 11, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Semen analysis is an important fertility test for infertile couples, and the test should be done before any treatments (even "just clomid") are prescribed. Many men experience anxiety over the test — and later, over the results. Your doctor will explain your results to you, and because different labs and doctors may use different normal value ranges, what your doctor considers normal or abnormal may differ from what you find in this article and elsewhere on the internet.

With that said, here are the semen health factors typically evaluated in a semen analysis, their normal values according to the World Health Organization's 2010 guidelines, and what abnormal results may mean.

The World Health Organization guidelines are based on percentiles, which are based on a group of men who fathered children in a year or less. The lower acceptable numbers represent the 5th percentile of this group. In other words, less than 5% of the men who fathered a child in the past year had semen parameter measurements below these cutoffs.

What this means is that having better or worse numbers doesn't necessarily mean you will or won't be able to father a child. The semen parameters are just guidelines to consider when investigating what may be causing infertility.

Semen Ejaculate Volume

What Is It: Semen is made up of more than just sperm. In fact, less than 5% of semen is made up of sperm. Healthy semen includes fluid from the testes (which is where the sperm come from), from the seminal vesicles (which includes important nutrients for the sperm), from the prostate gland (which includes zinc-rich fluid to maintain DNA stability of the sperm), and from the bulbourethral glands (which contains a mucus to help the semen swim).

What Is Considered Normal: Normal semen ejaculate is between 1.5 milliliters to 6 milliliters of fluid. This is about one-third of a teaspoon to a little over a teaspoon.

What Might Be Wrong if Results Are Abnormal: Low semen volume may be caused by an obstruction of the vas deferens (the duct that carries sperm from the testicles to the urethra), absence or blockage of the seminal vesicle, partial retrograde ejaculation, or a hormonal imbalance. Low volume may also be caused by stress over the test. (Speak to your doctor if this is true for you.) An abnormally high volume may be caused by inflammation of the reproductive glands.

Total Sperm Number

What Is It: This is the total number of sperm found in provided semen sample.

What Is Considered Normal: About 39,000,000 (or 39 x 10^6) sperm per ejaculate is considered the lower acceptable limit. Having a lower than normal count of sperm is sometimes called oligospermia. If no sperm cells are found, this is called azoospermia.

What Might Be Wrong if Results Are Abnormal: Having a lower sperm count may indicate a number of problems, including varicocele, infection, chronic or undiagnosed health problems like diabetes or celiac disease, problems with ejaculation like retrograde ejaculation, duct problems, hormonal imbalances, and exposure to toxic substances.

Abnormally low sperm counts can also be caused by certain medications, recent illness accompanied by high fever, and exposure of the scrotum to heat (as in a hot tub). Smoking, obesity, and excess alcohol intake has been linked to low sperm count. Often, the cause for low sperm count is never found.

Azoospermia may be caused by a duct problem, a hormonal imbalance, or a problem with the testes.

Sperm Concentration

What Is It: Sperm concentration is the number of sperm found in one milliliter of semen.

What Is Considered Normal: There should be at least 15,000,000 (or 15 x 10^6) sperm per millimeter.

What Might Be Wrong if Results Are Abnormal: Low sperm concentration may be part of an overall low sperm count, or it could be related to an abnormally high ejaculate volume. See above for more on these two issues.

Motility

What Is It: Motility is the percentage of sperm who move. For fertilization to occur, sperm must swim up the female reproductive tract to meet the egg. Being able to swim to their destination is essential. Total motility refers to any movement, while progressive motility refers to forward movement in either a line or in a large circle.

What Is Considered Normal: At least 40% of the sperm should be moving, and at least 32% should swim in a forward movement or in large circles.

What Might Be Wrong if Results Are Abnormal: Asthenozoospermia is the term used for poor sperm motility. Poor sperm motility may be caused by illness, certain medications, nutritional deficiencies, or poor health habits like smoking. Many of the causes of low sperm count can also cause poor motility. (See above.) Often the cause is never found.

Viability or Vitality

What Is It: Sperm viability refers to the percentage of live sperm in the semen sample. This is especially important to measure if sperm motility is low, so differentiate between live non-motile sperm and dead sperm.

What Is Considered Normal: At least 58% of the sperm cells should be viable.

What Might Be Wrong if Results Are Abnormal: Necrozoospermia is the term used when all sperm in the semen sample are dead. There are a variety of causes for necrozoospermia, including many of the same things that can cause low sperm count. (See above.)

Using a non-fertility-safe lubricant or regular condom can kill sperm, even if they don't contain spermicide. Be sure to disclose to your doctor if you used lubricant or a regular condom to produce your semen sample. There are fertility-approved lubricants and specialty condoms available for the collection of semen samples. Ask your doctor for more information.

Morphology

What Is It: Sperm morphology refers to the shape of the sperm cells. The lab technician closely examines a sample of sperm, checking to see approximately what percentage have a normal shape. The head, mid-section and tail are evaluated, as well as the measurements and proportions between each.

Before 2010, the World Health Organization had different requirements for sperm to be considered "normal" in shape. Labs may have evaluated sperm morphology according to the WHO criteria, or what is known as Kruger's Strict criteria. However, the 2010 WHO guidelines encourage the use of Kruger's Strict criteria, based on the research of Dr. T.F. Kruger and Dr. R. Menkeveld. Speak to your doctor to find out if they are using the outdated WHO criteria or Kruger's criteria.

What Is Considered Normal: At least 4% should have a normal shape.

What Might Be Wrong if Results Are Abnormal: Teratozoospermia is the term used for poor sperm morphology. Poor sperm morphology may be cause by the same things that can cause low sperm counts. (See above.)

Sperm morphology is poorly understood, and because the evaluation is somewhat subjective, scores can vary on the same semen sample, in the same lab, using the same scoring techniques. If sperm morphology alone is abnormal, but all the other semen parameters fall within normal limits, then male fertility may still be considered normal.

Liquefaction

What Is It: When semen is ejaculated, it is thick and gelatinous. This is to help it adhere to the cervix. The semen eventually liquefies to enable the sperm to swim better.

What Is Considered Normal: Semen should liquefy within 20 to 30 minutes of ejaculation.

What Might Be Wrong if Results Are Abnormal: Delayed liquefaction may indicate a problem with the prostate, the seminal vesicles, or the bulbourethral glands, which are also known as the male accessory glands.

If delayed liquefaction occurs, your doctor may follow up with a post-coital test (PCT). This fertility test evaluates the woman's cervical mucus after sexual intercourse. If sperm are found and moving normally, the delayed liquefaction is not consider a problem.

Semen pH

What Is It: Semen pH is a measurement of how acidic or alkaline the semen is. The seminal vesicle fluid should be more alkaline, while the prostate fluids should be more acidic. In combination, they balance each other out in the semen. Semen that is too acidic may kill the sperm or prevent fertilization.

What Is Considered Normal: The semen should have a pH greater than 7.2. Currently, there's no consensus on how more alkaline semen may affect fertility, and so there's no upper pH limit according to the WHO guidelines.

What Might Be Wrong if Results Are Abnormal: Usually, low pH is accompanied by other abnormal measurements, including low volume of semen or low sperm counts. This may point to an obstruction or absence of the vas deferens.

White Blood Cells (WBC)

What Is It: White blood cells are the cells that fight infection in the body. All semen includes white blood cells.

What Is Considered Normal: The white blood cell count should be less than 1,000,000 per milliliter of semen, or 1.0 x 10^6 per ml.

What Might Be Wrong if Results Are Abnormal: A higher than normal white blood cell count is known as leukocytospermia, and it may indicate infection. However, some men may have leukocytospermia and not have any active infection or male fertility impairment. In fact, anywhere from 5 to 20% of men tested may be found to have leukocytospermia.

If Your Results Are Abnormal

One abnormal semen analysis result is not necessarily a sign of impaired male fertility. Because so many factors can lead to a poor result, including recent illness or even stress over the test, your doctor will likely repeat the semen analysis in a few weeks. Speak to your doctor about what to expect next, and be sure to disclose any possible causes for poor results (including recent illness, a love of hot tubs or heated car seats, trouble producing a sample for the analysis, and all the medications you're currently taking.)

More on the male side of infertility:

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Sources:

Sandro C Esteves, Ricardo Miyaoka, and Ashok Agarwal. "An update on the clinical assessment of the infertile male." Clinics (Sao Paulo). 2011 April; 66(4): 691-700. doi: 10.1590/S1807-59322011000400026. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3093801/

Understanding Semen Analysis. Stony Brook State University of New York. Accessed May 27, 2013. http://www.uhmc.sunysb.edu/urology/male_infertility/SEMEN_ANALYSIS.html

WHO Laboratory Manual for the Examination and Processing of Human Sperm. Fifth Edition. Accessed May 27, 2013. http://whqlibdoc.who.int/publications/2010/9789241547789_eng.pdf

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