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A semen analysis reports volume, sperm concentration, total sperm number, motility, vitality and morphology against WHO lower reference limits — 1.4 mL, 16 million per mL, 39 million, 42%, 30%, 54% and 4% in the 2021 sixth edition. Those limits are fifth centiles of a fertile population, not thresholds for infertility.
A semen analysis measures the volume of the ejaculate, how many sperm it contains, how many are moving, how many are alive, and what proportion are normally shaped. It describes one sample on one day — not a man's fertility.
That distinction matters more than anything else on the page. The report is a laboratory description of a specimen. It is not a verdict, and on its own it cannot tell you whether you will conceive.
A standard report lists seven measurements, and they are not independent of each other:
Concentration and total sperm number are the pair most often confused, and the difference is worth understanding before you read your own figures. A low concentration in a large-volume sample can still add up to a normal total. A good concentration in a very small sample may not. Reading concentration alone, without looking at volume beside it, is one of the easiest ways to misread the report.
Motility is likewise reported twice, and the two numbers answer different questions. Total motility counts anything that moves. Progressive motility counts only forward movement. The second figure is the more informative of the two, and it is the one worth finding on the page.
The World Health Organization's 2021 sixth-edition lower reference limits are 1.4 mL volume, 16 million sperm per millilitre, 39 million total sperm, 42% total motility, 30% progressive motility, 54% vitality and 4% normal forms.
These are not averages, and this is the most commonly misread part of any report. Each figure is the fifth centile of a reference group of 3,589 men whose partners conceived within twelve months. In other words, 95% of men who had recently fathered a child scored above these numbers — and 5% of them scored below.
A man in that bottom 5% is, by definition, someone who fathered a child. The limits describe where the fertile population sits. They do not describe where fertility stops.
It follows that being marginally under one limit places you in the same range as one in twenty men who conceived without difficulty. It does not place you outside the fertile population. This is a statement about statistics, not reassurance — the arithmetic of a fifth centile simply does not support reading the number as a pass mark.
It also follows that a report which flags a single figure in red has made a presentational choice, not a clinical one. Laboratories differ in how they highlight results, and a highlighted value carries no more weight than the same value printed in black.
Because they may be citing different editions. The WHO fifth edition (2010) and sixth edition (2021) set slightly different limits, so the same sample can sit above the line on one report and below it on another.
The 2010 edition used 1.5 mL volume, 15 million per mL, 32% progressive motility, 58% vitality and 4% normal forms, drawn from roughly 2,000 men. The 2021 edition revised most of those from a larger group.
Check which edition your report names before comparing it to anything you have read online. If it does not say, ask the laboratory.
The practical effect of the change is smaller than it looks. A 2024 analysis in the Journal of Men's Health applied both sets of limits to the same samples and found 42.99% met every 2010 criterion against 43.55% for 2021 — a difference of 0.56%. The authors concluded the 2021 limits do not change the proportion of men who need treatment.
No. The WHO sixth edition states plainly that reference ranges and fifth centiles are insufficient to diagnose infertility, and it removed diagnostic labels such as normozoospermia and asthenozoospermia from the manual altogether.
This was a deliberate change of position, not a wording tweak. The manual now advises that multiple criteria must be applied before male infertility is diagnosed, and it discourages reading a single figure as a threshold that has been crossed.
If your report shows one value marginally below a limit, that finding on its own does not establish a diagnosis. It is a reason to repeat the test and to have the result read alongside your history and your partner's investigations — not a reason to move straight to treatment.
Removing the diagnostic labels was the substantive part of the change. Terms like normozoospermia and asthenozoospermia read as conditions a man either has or does not have, and they encouraged exactly the binary reading the manual now advises against. A man whose progressive motility reads 29% and a man whose reads 31% do not have different diagnoses. Under the old vocabulary they appeared to.
None of this means a low result is meaningless. Values well below the reference limits, or several parameters low together, or a finding that persists on a properly timed repeat, all warrant investigation. The point is narrower and more specific: a single figure a little under one limit, on one sample, is not the finding people take it for, and the manual that publishes those limits says so.
What the report cannot do is rank you. There is no score, no percentage chance of conception, and no way to convert seven measurements into an answer about your future. Any source that offers one from these numbers alone has gone beyond what the test supports.
WHO recommends two to seven days of abstinence before the sample is produced. Outside that window results shift, and a sample given after a very long or very short gap can look abnormal when nothing about the man has changed.
ESHRE suggests a narrower interval of three to four days. Either way, the abstinence period should be recorded on the report. If it is missing, the numbers are harder to interpret and worth querying — our guide to how to prepare for a semen analysis test covers what to do before the sample is produced.
Fever, recent illness and the time between production and analysis all affect the result too. A single poor sample collected in the weeks after an infection is a weak basis for any decision.
There is a further source of variation that has nothing to do with the man at all. The critical review of the WHO sixth edition notes that both biological variation within and between individuals, and technical variation between laboratories, affected the reference ranges of earlier editions.
Two laboratories can assess the same specimen and report different morphology figures, because morphology assessment in particular depends on trained human judgement — something we look at more closely in why sperm morphology is so often misread.
Practically, this means three things are worth checking on your own report before you read anything into it: the abstinence period, the WHO edition the limits are quoted from, and whether the sample was analysed promptly. If any of the three is absent, ask.
Yes. NICE advises offering a repeat confirmatory test when the first semen analysis is abnormal, ideally three months later, because a full cycle of sperm production takes about 74 days. Azoospermia or severe oligozoospermia should be repeated sooner.
The three-month interval is not administrative caution. It is the time needed for a new population of sperm to develop, so that the second sample reflects a genuinely different cohort rather than the same one measured twice.
Where no sperm are found at all, or very few, waiting three months is not appropriate — that repeat should happen as soon as it can be arranged, because the finding changes what needs investigating next. We cover that scenario separately in understanding azoospermia, its symptoms and treatment.
The practical consequence is that a first abnormal result is the start of an assessment, not the end of one. Decisions taken on a single sample are taken on incomplete information, and that includes decisions about treatment. If a clinic proposes a treatment path on the strength of one report, asking for the confirmatory test first is a reasonable question, not an obstructive one.
A standard semen analysis does not measure sperm DNA integrity, and it cannot predict whether conception will happen. It describes the sample in front of the laboratory, which is why one result is rarely enough to act on. DNA fragmentation is a separate test with its own indications — see the role of DNA fragmentation in male infertility.
It also says nothing about the other half of the picture. NICE recommends fertility investigations after a year of regular unprotected intercourse, and earlier where the female partner is 36 or over or there is a known predisposing factor. A semen analysis is one part of that assessment, not the whole of it.
If your report is abnormal on repeat testing, the next step is assessment by a urologist or andrologist rather than proceeding directly to treatment. Some causes are treatable and some are reversible, and that question is worth answering before anything else is decided.
Drafted by the IVFPulse editorial team against WHO, NICE and peer-reviewed sources, each cited below. Reference figures are quoted from the guidance named beside them and are not IVFPulse's own data. This article has not yet been reviewed by a named clinician.
The questions patients ask most often after reading their own report.
16 million per millilitre is the WHO 2021 lower reference limit, meaning 95% of men whose partners conceived within a year scored above it. A result at or just above 16 million sits at the bottom of that fertile range rather than in the middle of it. It is not a diagnosis on its own, and it should be read alongside motility, morphology and total sperm number.
WHO recommends two to seven days of abstinence, and ESHRE suggests a narrower three to four days. Producing the sample outside that window can shift the numbers enough to change how the report reads. Make sure the abstinence period is written on the report — without it, the result is considerably harder to interpret, and a repeat may be needed.
3% sits just below the WHO lower reference limit of 4%. That is not a diagnosis of infertility. The WHO sixth edition states that fifth-centile values are insufficient to diagnose infertility and removed labels like teratozoospermia from the manual. A single marginal morphology result is a reason to repeat the test, not to conclude anything.
Yes. NICE advises a repeat confirmatory test when the first analysis is abnormal, ideally about three months later, because a complete cycle of sperm production takes roughly 74 days. The exception is azoospermia or severe oligozoospermia, where the repeat should be arranged as soon as possible rather than delayed.