Preview for Kara’s review. Expanded educational draft · sources checked 12 October 2026 · clinical approval pending.
Each chapter’s key idea carries an evidence label: Strong, Moderate or Limited. What the labels mean
Reading a semen analysis without panic
Concentration describes sperm in each millilitre. Total sperm number describes the whole ejaculate. For example, 2 mL at 20 million sperm per mL gives approximately 40 million sperm in the sample. This is a counting example, not a pregnancy prediction.
Count
How many sperm are present? Concentration and total number use different units.
Movement
How do sperm move? Progressive movement means moving forward.
Shape
What proportion meet laboratory shape criteria? Shape does not show DNA quality.
Motility describes movement. Progressive sperm move forward; non-progressive sperm move but make little useful forward progress. Total motility includes both categories. Vitality describes how many sperm are alive, which is useful when movement is very low.
Morphology is the proportion meeting strict shape criteria under a microscope. A result of 4% does not mean only 4% are alive or that 96% carry abnormal DNA. Shape assessment, vitality and DNA testing are different measurements. A low morphology result needs interpretation alongside the other findings.
The WHO reference values below are fifth-centile values from men whose partners conceived naturally within a year. About 5% of those men had results below each value. They describe a reference population; they are not a minimum required for pregnancy. A result above them does not guarantee conception. The reference group was about 3,500 men from 12 countries, and most of Africa was missing or under-represented.
Fertile and infertile men overlap a lot. In a large US comparison of about 1,500 men, many with “low” results had fathered children and some with “normal” results were struggling; no single measure was diagnostic. One man’s sperm count can also swing by half or more from one sample to the next, so one test is never the whole story.
Your laboratory’s methods, reference information, collection details, medical history and partner’s assessment all matter. Avoid turning a report into a personal score or comparing two laboratories as if every measurement were interchangeable.
| Measure | Reference value | What it describes |
|---|---|---|
| Volume | 1.4 mL | Amount of semen |
| Concentration | 16 million/mL | Sperm in each millilitre |
| Total sperm number | 39 million | Sperm in the whole ejaculate |
| Total motility | 42% | Progressive + non-progressive movement |
| Progressive motility | 30% | Sperm moving forward |
| Vitality | 54% | Sperm that are alive |
| Morphology | 4% | Sperm meeting strict shape criteria |
They cannot diagnose infertility alone, measure your chance of pregnancy by themselves, or show that all sperm DNA is normal. Your own laboratory report and clinical assessment come first.
The WHO reference values describe the lowest 5% of men who recently fathered a child. They are a guide, not a pass-or-fail line.
Read more: WHO laboratory manual for human semen, sixth edition (2021) · Campbell et al. (2021): the data behind the WHO reference values · Guzick et al. (2001): semen results in fertile and infertile men · Keel (2006): how much one man’s results vary between samples · ASRM patient education: Sperm morphology (2023)
Preparing for a sample and understanding repeats
Follow the instructions from the laboratory doing your test. WHO guidance specifies two to seven days without ejaculation before a diagnostic semen test. Longer abstinence is not automatically better, and instructions for fertility treatment may differ.
Before you hand in a sample
- Follow your laboratoryIts instructions come first. WHO guidance specifies two to seven days without ejaculation.
- Collect the whole sampleUse the approved container. Tell staff if any is lost, especially the first portion.
- Keep to the deadlineIf home collection is allowed, confirm the delivery time and transport conditions.
- Mention what has changedRecent fever, illness, new medicines or collection difficulties help the result be read fairly.
Use the container supplied or approved by the laboratory and aim to collect the entire sample. Tell staff if any is lost, especially the first portion, which can contain many sperm. Ordinary condoms and lubricants may affect the sample; ask the laboratory about suitable options if collection is difficult.
If home collection is permitted, confirm the delivery deadline and transport conditions in advance. Record the collection time and abstinence interval. Mention recent fever, illness, medication changes and any collection difficulties so the result can be interpreted fairly. A high fever can lower sperm concentration by about a third for two to three months, so a test done soon after a fever may need repeating.
Semen measures naturally vary. If a result is abnormal, European guidance recommends at least two tests before drawing conclusions (a strong recommendation); if every value is within the reference values, the WHO suggests not repeating it. If no sperm or very few are found, the test is usually repeated as soon as possible, with specialist review. Guidelines differ on how long to wait before a repeat, as the box below shows. Your clinician should set the interval; do not delay assessment simply to finish a lifestyle programme.
If a semen test is abnormal, it should be repeated before any conclusion is drawn.
Read more: WHO laboratory manual for human semen, sixth edition (2021) · WHO guideline for the prevention, diagnosis and treatment of infertility (2025) · EAU guideline: Male infertility · NICE NG257: Fertility problems: assessment and treatment (2026) · South African National Department of Health: National clinical guidelines for safe conception and infertility (2020) · Carlsen et al. (2003): fever and semen quality · NHS: Low sperm count
Sperm DNA testing: when does extra information help?
Sperm DNA fragmentation describes breaks in the genetic material sperm carry. A routine semen analysis does not measure it directly, and a sperm’s appearance cannot tell you its DNA result.
Several different tests exist, called TUNEL, SCSA, SCD and Comet. Each uses its own method and cut-off, often somewhere between 20% and 30%, so a “high” result from one laboratory cannot be compared directly with a result from another.
The major guidelines disagree about who should be tested, as the box below shows. None recommends the test for every man as part of a first assessment. Before testing, ask what decision would change with the result, and whether that change is supported by evidence on outcomes that matter to you, such as a live birth.
A sperm DNA test is not part of a routine first assessment. It may be offered in selected situations, such as repeated miscarriage.
Read more: WHO laboratory manual for human semen, sixth edition (2021) · Santi et al. (2018): sperm DNA fragmentation cut-offs, a review · NICE NG257: Fertility problems: assessment and treatment (2026) · EAU guideline: Male infertility · AUA/ASRM Male Infertility guideline, amended 2024 · ESHRE good practice recommendations on add-ons in reproductive medicine (2023)
Sperm DNA: what the results can and can’t tell you
Kara’s research area: Kara designed research on how sperm DNA integrity changes as men get older. The findings below come from the largest published studies.
Higher levels of sperm DNA damage are consistently linked with poorer outcomes. In couples trying naturally, very high levels were linked with a lower chance of conceiving each month. In one large clinic study, results above 30% on one test were linked with lower IUI success. Across IVF studies, high DNA damage was linked with lower pregnancy rates, and less so with ICSI.
High DNA damage has been linked with about twice the risk of miscarriage in fertility-clinic studies, and men whose partners have had repeated miscarriages tend to have more DNA damage. Whether treating it prevents further losses is unknown.
But a link is not the same as a useful test. A review of how well these tests predict pregnancy after IVF or ICSI found them only “fair” at best, and two of the common tests were poor. The result also could not show whether IVF or ICSI would work better for a couple.
Some things are linked with more DNA damage: smoking, a varicocele, poorly controlled blood sugar, air pollution and being 50 or older. Stopping smoking is worthwhile for many reasons.
Steps that can lower DNA damage have not been shown to lead to more babies. Repairing a varicocele that can be felt on examination lowered DNA damage by about 7 percentage points on average, in studies without comparison groups. A one-day gap before a sample, rather than three days, made no clear difference to DNA damage or pregnancy rates in a small randomised trial of IUI. Antioxidants lowered DNA damage a little, by about 4 percentage points on average after three months in a 2025 review, but that has not been shown to lead to more babies, and the UK’s NICE advises against offering them for this.
Some clinics offer to use sperm taken directly from the testis when DNA damage is high, because testicular sperm tend to carry less damage. Early studies look promising, but there are no proper randomised trials, it involves surgery, and the guidelines disagree, as the box below shows.
High sperm DNA damage is linked with lower pregnancy rates and more miscarriage, but today’s tests cannot predict what will happen for one couple.
Read more: Spanò et al. (2000): sperm chromatin damage and natural conception · Bungum et al. (2007): sperm DNA and IUI, IVF and ICSI outcomes · Simon et al. (2017): sperm DNA damage and IVF and ICSI, a review · Robinson et al. (2012): sperm DNA fragmentation and miscarriage, a review · McQueen et al. (2019): sperm DNA and recurrent pregnancy loss, a review · Cissen et al. (2016): how well sperm DNA tests predict pregnancy · Szabó et al. (2023): factors linked with sperm DNA damage, a review of 190 studies · Lira Neto et al. (2021): varicocele repair and sperm DNA, a review · Szabó et al. (2025): treatments that lower sperm DNA damage, a review of 86 studies · Kabukçu et al. (2021): abstinence time before IUI, a randomised trial · Esteves et al. (2017): testicular or ejaculated sperm for high DNA damage, a review · Khoo et al. (2024): testicular sperm for high DNA damage, an updated review · NICE NG257: Fertility problems: assessment and treatment (2026) · EAU guideline: Male infertility · AUA/ASRM Male Infertility guideline, amended 2024
What you may be wondering
What if I lose some of the sample?
Tell the laboratory. An incomplete collection can affect interpretation. Follow the laboratory’s instructions rather than hiding a collection difficulty.
Should everyone have a sperm DNA test?
No major guideline recommends it for everyone. The UK’s NICE advises against it; European and US urologists suggest it in selected situations, such as repeated miscarriage. Ask what clinical decision a result would change.
Common worries, explained carefully
“Low morphology means most sperm are dead.”
Morphology describes shape. Vitality describes whether sperm are alive, and motility describes movement. These are separate measurements.
“One result tells us everything.”
Collection, natural variation, illness and clinical history can affect interpretation. Your clinician may recommend another sample.
“A reference value is a pass-or-fail fertility score.”
WHO lower reference values describe a reference population. They cannot determine an individual’s chance of pregnancy by themselves.
“Lowering sperm DNA damage is proven to lead to a baby.”
Some steps lower DNA damage, but none has yet been shown in trials to increase live births.
The terminology, translated
- Concentration
- The number of sperm per millilitre of semen.
- Total sperm number
- The number of sperm in the whole ejaculate.
- Motility
- How sperm move. Progressive motility describes forward movement.
- Morphology
- Sperm shape assessed against laboratory criteria.
- Vitality
- The proportion of sperm that are alive.
- DNA fragmentation
- Breaks in sperm DNA; not measured directly by routine semen analysis.
- TUNEL, SCSA, SCD and Comet
- Names of different sperm DNA tests. Each has its own method and cut-off.
- What does the full pattern of results suggest?
- Was the sample complete, and were the collection instructions met?
- Should I repeat the test, and when?
- Would DNA testing change a decision in our circumstances?
- If a DNA test is suggested, which test and cut-off does the laboratory use?
Videos on this guide
Videos on these questions are coming to the channel:
- What Is a Semen Analysis?
- Understanding Sperm Count
- Understanding Sperm Motility
- Understanding Sperm Morphology
Sources & further reading
Sources 26 studies and guidelines Show the research
Prepared using Kara’s research library and checked against the linked clinical and patient-education sources. The explanations and new diagrams are original educational adaptations.
- WHO laboratory manual for human semen, sixth edition (2021)
- Campbell et al. (2021): the data behind the WHO reference values
- Guzick et al. (2001): semen results in fertile and infertile men
- Keel (2006): how much one man’s results vary between samples
- ASRM patient education: Sperm morphology (2023)
- WHO guideline for the prevention, diagnosis and treatment of infertility (2025)
- EAU guideline: Male infertility
- NICE NG257: Fertility problems: assessment and treatment (2026)
- South African National Department of Health: National clinical guidelines for safe conception and infertility (2020)
- Carlsen et al. (2003): fever and semen quality
- NHS: Low sperm count
- Santi et al. (2018): sperm DNA fragmentation cut-offs, a review
- AUA/ASRM Male Infertility guideline, amended 2024
- ESHRE good practice recommendations on add-ons in reproductive medicine (2023)
- Spanò et al. (2000): sperm chromatin damage and natural conception
- Bungum et al. (2007): sperm DNA and IUI, IVF and ICSI outcomes
- Simon et al. (2017): sperm DNA damage and IVF and ICSI, a review
- Robinson et al. (2012): sperm DNA fragmentation and miscarriage, a review
- McQueen et al. (2019): sperm DNA and recurrent pregnancy loss, a review
- Cissen et al. (2016): how well sperm DNA tests predict pregnancy
- Szabó et al. (2023): factors linked with sperm DNA damage, a review of 190 studies
- Lira Neto et al. (2021): varicocele repair and sperm DNA, a review
- Szabó et al. (2025): treatments that lower sperm DNA damage, a review of 86 studies
- Kabukçu et al. (2021): abstinence time before IUI, a randomised trial
- Esteves et al. (2017): testicular or ejaculated sperm for high DNA damage, a review
- Khoo et al. (2024): testicular sperm for high DNA damage, an updated review
Fertility is a shared picture
For every couple, the health and results of both the man and the woman shape the plan. These Fertility Library topics sit alongside this guide.
