A standard semen analysis reports about a dozen values. Most men walk out of the clinic with two numbers in their head: concentration and motility. The remaining values matter because they describe different things. They tell you whether the sperm are shaped normally, whether the fluid environment supports them, whether the immune system is involved, and whether the DNA inside the sperm is intact. If you only look at count and motility, you are reading two lines of a twelve-line report.
The World Health Organization sets these reference limits using samples from men who fathered a child within 12 months. The lower limit is the 5th percentile, so falling below a value simply places you outside what 95 percent of fertile men produce (WHO Laboratory Manual for the Examination and Processing of Human Semen, 2010, updated 2021). A single low value is not a diagnosis. It is a reason to repeat the test and talk with a doctor.
Morphology
Morphology describes the percentage of sperm with a normal shape under strict criteria, often called Kruger criteria. A normal sperm has an oval head with an intact acrosome cap covering roughly half the head, a midpiece about the length of the head, and a single straight tail. The WHO reference value for normal morphology is 4 percent. That number sounds low because most sperm in a healthy sample are shaped abnormally, even in fertile men. The threshold is low because the strict criteria set a high bar for what counts as normal.
Why shape matters
The acrosome contains enzymes the sperm uses to digest the outer layer of the egg. A misshapen head can mean a reduced acrosome or poorly packaged DNA. Neck and tail defects can interfere with forward movement. Researchers debate how much isolated low morphology predicts natural fertility. A man with 2 percent normal forms can conceive without assistance, and a man with 12 percent can struggle. Morphology carries more weight when other parameters also look abnormal or when an embryologist is selecting individual sperm for intracytoplasmic sperm injection, known as ICSI.
Volume and pH
Volume sits at 1.5 mL or higher on the 2010 WHO reference values. Most of the volume comes from the seminal vesicles and prostate, not the testes. The testes contribute the sperm. The glands contribute the transport fluid. A low volume can point to retrograde ejaculation, where semen passes backward into the bladder instead of forward, or to a blockage or an incomplete collection. Volume matters because it changes the total number of sperm delivered even when concentration looks normal.
pH should be 7.2 or higher. A low pH suggests the seminal vesicle contribution is missing, which happens with congenital absence of the vas deferens or ejaculatory duct obstruction. A very high pH can signal infection in the accessory glands. pH is a clue about the plumbing. It tells you little about the sperm themselves.
Vitality
Vitality, sometimes called viability, measures the percentage of sperm that are alive, using a dye exclusion test. This parameter separates two problems that look identical under a microscope: a sample full of dead sperm and a sample full of living sperm that cannot move. If vitality is high while motility is zero, the issue may sit in the tail or the energy machinery. If vitality is low, the sperm are dying during production or storage. WHO sets the reference at 58 percent or more alive.
Liquefaction and viscosity
Fresh semen is a gel. Within 20 to 30 minutes, enzymes from the prostate liquefy it so sperm can swim freely. If a sample fails to liquefy or stays thick, the lab notes it. Persistent non-liquefaction can signal a prostate function problem. Viscosity is graded by how the sample stretches when drawn into a pipette. It matters because thick fluid slows sperm movement and makes the sample harder to analyze accurately.
White blood cells and agglutination
Leukocytes should be under 1 million per milliliter. Higher counts suggest inflammation or infection somewhere in the reproductive tract. The lab may use a staining test to tell leukocytes apart from immature germ cells, because round cells look similar under the microscope. Elevated white blood cells can indicate prostatitis or a seminal vesicle infection. Sometimes the infection is the reason for poor sperm parameters, and treating it may change the picture.
Agglutination is a related note on the report. It means sperm are clumping together. Moderate to severe agglutination can suggest antisperm antibodies, where the immune system treats sperm as foreign. Mild agglutination can be a collection artifact. Clumped sperm cannot swim effectively, so the lab flags it.
DNA fragmentation
DNA fragmentation is not part of the basic WHO panel, but more clinics order it alongside a standard analysis. The test measures the percentage of sperm with broken DNA strands, using assays such as the sperm chromatin structure assay, TUNEL, or COMET. Sperm with high DNA fragmentation can swim normally and fertilize an egg, and then the embryo arrests or the pregnancy miscarries. The clinical usefulness of this test is actively debated, and no universal threshold exists. Some labs use reference thresholds in the 25 to 30 percent range depending on the assay, but values differ between labs. Think of DNA fragmentation as a stress test for the sperm's genetic cargo. A high result may help explain recurrent loss or failed IVF cycles.
Concentration and total count
Concentration is sperm per milliliter. Total count is concentration multiplied by volume. A man can have a concentration of 20 million per milliliter, which looks normal, and a volume of 0.5 milliliters, giving a total count of 10 million. Concentration alone can be misleading. The total number per ejaculate is the more useful figure when thinking about how many sperm are available.
What to do with the report
If your report shows abnormal values, the standard next step is a repeat test after 2 to 3 months. Sperm production takes about 74 days from start to ejaculation. Changes to diet, sleep, alcohol, or heat exposure take that long to show up in a sample. A single abnormal result is not a diagnosis. Two abnormal samples three months apart are worth acting on.
Before the next test, check the collection conditions. The factors below all affect the sample:
- Fever in the past 3 months
- Recent illness
- Certain medications
- Time since last ejaculation
- The collection method
Labs typically ask for 2 to 5 days of abstinence. If any of those were off, tell the ordering doctor before the repeat test. The result is only as good as the sample.
If the clinic gives you a one-line summary, ask for the full lab report. Every parameter above is on it. Read the whole thing.
This content is for educational purposes only and is not medical advice. Oakman products are designed for physical comfort and cooling; they make no claims about fertility, sperm quality, or hormone levels. Consult a healthcare professional for personalized advice.