Written by Francesca Steyn, NMC-registered fertility practitioner
A semen analysis report is a page of numbers with very little explanation attached, which is why so many men read theirs twice and still feel none the wiser. Here are semen analysis results explained in plain English: what each measurement is, what the reference ranges are actually based on, and how much weight to put on a single sample. No medical background needed.
What a semen analysis actually measures
Your report is the record of one sample examined in a laboratory. The numbers describe how much semen there was, how many sperm were in it, how they were moving, and what shape they were. Nothing more mysterious than that.
Most laboratories, including NHS andrology labs, work to the methods set out in the World Health Organisation laboratory manual. The sixth edition, published in 2021, is the current standard, and it is what a Malebox report is measured against. A fuller report covers nine markers: semen volume, total count, concentration, progressive motility, non-progressive motility, total motility, immotile sperm, vitality, and morphology.
The main measurements and their reference limits
These are the lower reference limits from the WHO sixth edition. They are the figures your own numbers will be printed alongside.
- Semen volume, 1.4 ml. How much fluid was in the sample. Volume matters because sperm need something to travel in, and because total count is calculated from it.
- Sperm concentration, 16 million per ml. How densely packed the sperm are in each millilitre of semen.
- Total sperm count, 39 million. Concentration multiplied by volume, giving the number of sperm in the whole sample.
- Total motility, 42 per cent. The share of sperm that are moving at all.
- Progressive motility, 30 per cent. The share that are swimming forwards rather than twitching on the spot. This is the movement that counts for reaching an egg.
- Morphology, 4 per cent normal forms. The share of sperm with a textbook head, midpiece and tail.
- Vitality, 54 per cent. The share of sperm that are alive, judged by whether the cell membrane is intact. Useful when motility is low, because it separates sperm that are dead from sperm that are alive but sluggish.
The 4 per cent morphology figure surprises almost everyone. It is not a typo. Human sperm are irregular by nature, and a sample where 95 per cent of sperm look unusual under strict criteria can still be entirely unremarkable.
What the reference ranges really mean
This is the part that changes how the whole report reads.
The WHO limits are not a boundary between fertile and infertile. They are the fifth centile of a reference group of around 3,500 men whose partners conceived naturally within twelve months. In other words, 95 per cent of that recently fertile group sat above each figure, and 5 per cent of them sat below it while still going on to conceive.
So a number below a reference limit does not mean conception will not happen, and a number above it is not a guarantee that it will. The ranges are a guide for interpretation, not a verdict on you. That is why a result should always be read as a whole rather than one line at a time, and ideally read with someone who can put it in context. If you want the fuller picture on what counts as typical, our guide to what a normal sperm count looks like goes into the detail.
The clinical words on your report, translated
Reports sometimes carry a one-word summary in Latinised form. They sound far more dramatic than they are, and each one simply names which measurement fell below its reference limit.
- Normozoospermia: all measured values sat within the reference ranges.
- Oligozoospermia: sperm concentration or total count below the reference limit.
- Asthenozoospermia: motility below the reference limit.
- Teratozoospermia: fewer normal forms than the morphology limit.
- Oligoasthenoteratozoospermia, or OAT: all three of the above in the same sample.
- Azoospermia: no sperm found in the sample. This one does warrant prompt clinical follow-up.
None of these are diagnoses of infertility. They are descriptions of one sample on one day.
What this means in practice
Semen quality varies. The same man can produce noticeably different results weeks apart, influenced by how long since the last ejaculation, a recent illness or fever, sleep, and how the sample was collected and transported. A single set of numbers is a snapshot, not a settled fact.
That variability is built into UK clinical practice. NICE guidance is that if a first semen analysis is abnormal, a repeat confirmatory test should be offered, ideally around three months later. The three months is not administrative caution: sperm take roughly 74 days to develop, so a three-month gap means the repeat is measuring a genuinely new cohort of sperm rather than the same one twice. The exception is a very low or absent count, where the repeat should happen sooner.
Practically, that gives you three sensible responses to a report. If everything sits within range, you have a baseline and a date. If one or two figures sit below, a repeat after about three months tells you whether it was a blip or a pattern. And if the report shows no sperm, or you have had two abnormal results, that is the point to see a GP or specialist, who may examine the scrotum and testes and check testosterone and gonadotrophin levels.
What is worth insisting on either way is an explanation. A report you cannot interpret has told you very little. Every Malebox home sperm test at £240 includes a video consultation where a fertility practitioner walks through each marker with you, which is the part most routes leave out.
Frequently Asked Questions
Q: What is a normal semen analysis result?
A: Under the WHO sixth edition, the lower reference limits are 1.4 ml volume, 16 million sperm per ml, 39 million total count, 42 per cent total motility, 30 per cent progressive motility, 4 per cent normal forms and 54 per cent vitality. Results above these sat within the range seen in recently fertile men.
Q: Does a low sperm count mean I am infertile?
A: No. The reference limits mark the fifth centile of men whose partners conceived naturally within a year, so some men below them conceived without difficulty. A below-range figure means the result is worth repeating and discussing, not that conception is off the table.
Q: Why is only 4 per cent normal morphology considered acceptable?
A: Because sperm are assessed against strict criteria where almost any deviation in head, midpiece or tail counts as abnormal. Even among men with no fertility difficulties, the large majority of sperm are irregular, so 4 per cent normal forms sits within the expected range.
Q: How soon should I repeat a semen analysis?
A: NICE guidance suggests a repeat confirmatory test around three months after an abnormal result, because sperm take roughly 74 days to develop and a three-month gap measures a fresh cycle. If the sample showed no sperm or a very low count, the repeat should be arranged sooner.
Q: Can my results change between tests?
A: Yes, and often noticeably. Time since last ejaculation, recent illness or fever, sleep, and how the sample was collected and handled all affect the figures. This is exactly why one result is treated as a starting point rather than a conclusion.
A semen analysis is one of the few parts of fertility that gives you something concrete to work with. Read alongside the reference ranges, and with the context of how much a single sample can vary, your report stops being a page of unexplained numbers and becomes a straightforward account of where things stand right now.
Francesca Steyn is an NMC-registered fertility practitioner with over 20 years in reproductive health. She has served on the NICE guideline committee and the HFEA legislative reform group.
