Semen Analysis

Medically Reviewed by Traci C. Johnson, MD on November 12, 2022
5 min read

Semen analysis is a test of a man’s sperm and semen. Also known as a sperm count or male fertility test, its results show how many sperm are released, as well as how they're shaped and how well they move

Semen is the thick fluid that comes from men’s penis when they ejaculate during sexual activity. It carries sperm out of a man’s body so it can fertilize an egg and create an embryo (the first stage of pregnancy).

If you and your partner are having trouble getting pregnant, one of the first tests your doctor will likely ask for is a semen analysis.

While both men and women can have problems, issues with male fertility can play a part in as many as half of all infertility cases. And male infertility is often caused by low sperm production.

Another reason you might need a semen analysis is to make sure a vasectomy (a procedure to prevent pregnancy) was successful. It’s usually done 8 to 16 weeks after the surgery to see if you’re still making any healthy sperm.

In order to test your semen, your doctor will ask you for a semen sample:

  • You’ll probably be asked to ejaculate into a collection cup in a private room at your doctor’s office.
  • Sometimes you can collect your sample at home. If so, you’ll have to keep it at room temperature and get it to your doctor or lab within 1 hour. Some doctors provide you with a special condom that collects your semen during sex.
  • Don’t use lubricants when you collect your sample because they can affect how easily your sperm can move around.

While at-home tests can give you a quick check of your sperm count, these won’t measure other things about your sperm, like shape or movement. So a normal result on a home test doesn’t guarantee fertility. You’ll need to talk with your doctor to get a complete picture of what’s going on.

Here are a few things to keep in mind before giving the sample:

  • Your doctor may ask you not to have sex or masturbate for 2 to 5 days before your test to make sure your sperm count will be as high as possible.
  • Don’t avoid ejaculation for more than 2 weeks before your test. That can result in a sample with sperm that are less active.
  • It’s best not to drink alcohol before your semen analysis.

You also should tell your doctor about any medications or herbal supplements you’re taking. Drugs that can affect your results include:

  • Testosterone: Supplements that boost this hormone can send the wrong signal to your body and make it stop producing natural testosterone and sperm. It can lead to a low count or lack of sperm.
  • Anabolic steroids: Used to build muscle, these drugs can affect your body’s sperm production.
  • Marijuana: The THC (tetrahydrocannabinol) in marijuana can slow down your sex drive and keep your body from making testosterone and sperm the way it should.
  • Opiates: These can lower your sperm count and affect testosterone production, too.

To get the most accurate results, your doctor will want to test more than one sample. You will need to provide another sample within 2 to 3 weeks. This is because semen samples from the same man can vary. You may even need to provide two to three samples over a 3-month period.

Once a lab gets your semen sample, it will look at it under a microscope. This will provide a wealth of information, including:

How many sperm there are (concentration). A normal sperm count is at least 15 million sperm per milliliter of semen. Your sperm count is considered low if you have less than that.

How your sperm are moving (motility). Your doctor will look at how many sperm are moving and how well they move. Ideally, 50% or more of your sperm sample should be active.

What your sperm look like (morphology). The size and shape of your sperm affect how well they can fertilize an egg. Normal semen will have at least 4% normally shaped sperm.

In addition to analyzing your sperm, your doctor will also find out other details from your sample, including:

Volume. They’ll note how much semen you were able to provide for your sample. A normal amount is at least 1.5 milliliters, or about half a teaspoon. If your sample is less than that, it could mean that your seminal vesicles aren’t making enough fluid or are blocked. You could also have a problem with your prostate.

Chemical makeup. Your pH level measures the acidity in your semen. Normal pH is between 7.1 and 8.0. A low pH level means you have acidic semen. A high pH level means it’s alkaline. An abnormal pH can affect the health of your sperm and how well it moves.

Liquefaction time. Normal semen comes out thick during ejaculation. Liquefaction time measures how long it takes before it becomes liquid. It should take about 20 minutes. If yours takes longer, or doesn’t become liquid at all, it could mean there’s a problem.

Fructose level. If your doctor doesn’t find any sperm in your semen analysis, they will probably check it for seminal fructose, which is produced by your seminal vesicles. Low levels, or no fructose, could mean you have an obstruction.

If your semen analysis results are abnormal, your doctor will likely want you to have other tests to figure out your specific fertility problem.

Test results aren’t always a true indicator of fertility, as men with low sperm counts can still be fertile and vice versa. Talk with your doctor about what your specific numbers mean.

Several things can affect a semen analysis, including:

  • Using lubricants or condoms that have lubricants in them
  • Drinking alcohol
  • Smoking
  • Using recreational drugs
  • Some prescribed medications

Results can be different depending on age, gender, and general health as well.

Depending on your results, your doctor may recommend other tests, including:

  • Sperm antibodies. This provides more information about your sperms’ ability to penetrate an egg or their swimming speed and direction.
  • Sperm penetration assay (SPA). Also known as a hamster egg test, this checks sperms’ ability to break through the outer wall and fuse with the egg.
  • Hemizona assay test. This also tests sperms’ ability to fuse with an egg.
  • Cervical mucus penetration test (Pentrak). This is done to see how well sperm can swim in a woman’s cervical mucus to get to the egg.