Doctors monitor several semen parameters when assessing male fertility. During a lab test you will deliver your sample to the doctor or lab technician, who will analyze it on a microscope. Following your test you will receive a lab report with your scores. What do these numbers all mean? We’ll do our best to help you sort it all out. If you are planning to schedule a semen analysis, make sure to also read our article on preparing for a semen analysis . You may also want to check out our fertility quiz to identify risk factors and get personalized recommendations for how to optimize your fertility.

Fertility is all about probability. Out of the millions of sperm released into the vagina following sex only a handful even come close to the egg. Even these few have to be healthy enough to survive long enough in the female body for an egg to show up. So, when trying to conceive, the more healthy sperm you have, the better the odds that one of them will make it alive to the egg. However, it is important to remember that just one little sperm is all it takes, so even if you have a low count it is possible to get pregnant naturally although with reduced monthly odds.

The semen analysis measures a number of parameters that affect the chances of the sperm reaching the egg. Some of the parameters are indicators of sperm production and health (see How Sperm are Made) others relate the the quality of the semen and its ability to help sperm along the journey to the egg.

Parameters measured during a semen analysis

The World Health Organization (WHO) has compiled extensive data on each of these parameters for healthy men that were able to conceive following less than 12 months of trying. We have included the WHO “normal” range for each parameter, which we define as falling between the 5th and 95th percentile of healthy men. (WHO Guidelines for Semen Analysis)

Sperm Count

This number tells you the approximate number of sperm cells present in your semen sample. It may be reported as the sperm concentration (millions of cells per milliliter of semen) as well as total count (millions of cells in the ejaculate). The total count is calculated by simply multiplying the sperm concentration by the volume of the ejaculate.

Male fertility basically comes down to a numbers game. Of course you really only need one good sperm cell to conceive a child. But your chances are much better if you’re armed with millions of good sperm cells. Thus the higher your sperm count, the more likely you are to successfully conceive.

If your count is a little low, don’t fear there are lots of things you can do to increase your sperm count.

WHO Normal Range (5th – 95th percentile): 15 – 213 million cells per mL

Sperm Motility (%)

It’s not only important to have high numbers of sperm cells present, they also need to be able to swim and accomplish their mission. The percent motility tells you the fraction of your sperm cells that are motile (swimming).

Some laboratory reports will break down this category further into sub-categories including rapid progression, slow progression, and forward progression, which quantify the speeds of swimming cells as well as their directionality (healthy sperm swim forward). These parameters are more difficult to quantify and can vary considerably based on the technician performing the analysis. Therefore these more subjective parameters are often ignored by physicians. The important metric to consider is how many of the cells are swimming at all.

WHO Normal Range (5th – 95th percentile): 40 – 78%

Semen Volume (mL)

The ejaculate volume is measured primarily to estimate the total number of sperm cells delivered to the female. However, an abnormally low ejaculate volume may prevent sperm cells from successfully navigating their trip through the female’s reproductive tract. An abnormally high ejaculate volume could be a symptom of an infection. Your doctor would likely order additional tests if suspecting that their many be an infection.

WHO Normal Range (5th – 95th percentile): 1.5 – 6.8 mL

Sperm Morphology (%)

Morphology denotes the fraction of your sperm cells that have a normal shape. Sometimes sperm heads or tails have an abnormal size or aspect ratio. Sperm cell morphology is typically only measured in cases where the couple is assessing their options for in vitro fertilization (IVF). Morphology has been shown to correlate with the chances of successful conception via IVF. However, for conventional intercourse or artificial insemination, the morphology parameter is basically irrelevant. For assessing your chances of conception via “the old fashioned way”, just pay attention to your count and motility.

WHO Normal Range (5th – 95th percentile): 4 – 44%

Other Parameters

Your semen report will likely include several other parameters, which tend to be less important but still may affect your chances of conception or be indicators of your overall health:

pH: An acidic (low pH) semen sample may be indicative of a blockage in your seminal vesicles. A basic (high pH) semen sample may be due to an infection. If the pH is abnormal either way, your doctor will likely order additional tests. Normal Range: 7.2 – 8.0

Viscosity: Viscosity is a measure of how “thick” or “watery” the sample is. Highly viscous semen may inhibit sperm motility and make it more difficult for your sperm cells to reach the female’s egg. The technicians typically measure this parameter somewhat subjectively and will give you a score of Low, Normal, or High. Normal Range: Normal

Liquefaction Time (minutes): Fresh semen samples will “liquefy” over time due to enzymes in the sample that break down the gelatinous structure of the seminal fluid. This process helps reduce the viscosity of the sample and therefore improve the sperm cells’ ability to swim. Some doctors will measure how long the semen sample requires to fully liquefy, especially if an earlier test revealed a high semen viscosity. Normal Range: 15 – 60 minutes

Fructose (μmol per ejaculate):Don’t get too excited, but your semen sample is naturally somewhat “sweet”. Doctors measure Greater than 13 μmol per ejaculate.

White Blood Cells(WBC, 10^6 cells per mL): White blood cells (or “leukocytes”) are normally present in trace amounts in a semen sample. A high concentration of WBCs in your sample may be indicative of an infection. WBCs are a major force in your body’s immune system, so if you have an infection your body naturally makes more WBCs to help fight it off. Your doctor will conduct more tests if suspecting an infection may be present. Normal Range: Less than 1 million cells per mL

Vitality (%): Vitality measures the fraction of sperm cells that are alive. Sperm cells have a somewhat short life span, therefore a normal ejaculate will include some percentage of dead cells. Too many dead cells could indicate a problem with your plumbing. WHO Normal Range (5th – 95th percentile): 58 – 91%