Male factor infertility is identified in approximately 40–50% of all couples who have difficulty conceiving, yet men are still routinely the last to be evaluated — or evaluated incompletely. For a broader overview of causes and treatment options, see the male factor infertility condition guide. A basic semen analysis can be obtained in a single office visit, costs less than most female fertility tests, and provides critical information that changes the clinical approach for half of all infertile couples.
This guide covers every fertility test available to men: the semen analysis and WHO 2021 reference values, hormonal panels, genetic testing, sperm DNA fragmentation, testicular ultrasound, and the indications for seeing a reproductive urologist.
The Semen Analysis: The Foundation of Male Fertility Testing
The semen analysis is the first and most important test in male fertility evaluation. It evaluates multiple parameters of the ejaculate and provides a detailed picture of sperm production and function.
How to Collect a Semen Sample Correctly
Results are only as reliable as the collection method. Standard instructions:
- Abstain from ejaculation for 2–5 days before the test (not more, not less)
- Collect by masturbation into a sterile, lab-provided container
- Keep the sample at body temperature during transport; analyze within 60 minutes of collection
- Avoid lubricants unless specifically labeled sperm-safe
- Inform the lab if any portion of the sample was lost during collection
Semen analysis results are significantly variable between samples from the same man. A single abnormal result should always be confirmed with a second analysis 4–6 weeks later before drawing clinical conclusions.
WHO 2021 Semen Analysis Reference Values
The World Health Organization updated its semen reference values in 2021 (6th edition of the Laboratory Manual). These are the lower reference limits — the 5th percentile of values in men whose partners conceived within 12 months:
| Parameter | WHO 2021 Lower Reference Limit |
|---|---|
| Semen volume | 1.4 mL |
| Sperm concentration | 16 million/mL |
| Total sperm count per ejaculate | 39 million |
| Total motility (progressive + non-progressive) | 42% |
| Progressive motility (PR) | 30% |
| Non-progressive motility (NP) | — |
| Immotile sperm | <20% (soft threshold) |
| Normal morphology (Kruger strict criteria) | 4% |
| Sperm vitality (live sperm) | 54% |
| pH | >7.2 |
| Leucocytes | <1 million/mL |
Note: The 2021 reference limits are slightly higher for concentration (raised from 15 to 16 million/mL) and motility compared to the 2010 manual, reflecting improved data from fertile reference populations.
Understanding Each Parameter
Sperm Concentration Measured in millions per milliliter. Below 16 million/mL is oligospermia (low count). Severe oligospermia is generally defined as <5 million/mL. Azoospermia means no sperm found in the ejaculate on two confirmed samples.
Total Sperm Count Concentration × volume. More clinically meaningful than concentration alone because a man with high concentration but low volume may have an overall adequate total count — or vice versa.
Progressive Motility (PR) The percentage of sperm swimming actively forward. Progressive motility is the most clinically important motility parameter — sperm must be able to swim toward and penetrate the egg. Below 30% is asthenospermia (poor motility).
Morphology (Kruger Strict Criteria) The percentage of sperm with a normal shape by strict Kruger criteria — arguably the most stringent classification system in clinical use. At <4% normal forms (teratospermia), fertilizing ability is reduced, though normal morphology alone has limited predictive value for natural conception. Severe teratospermia (<1%) raises concern for specific structural defects.
Semen Volume Low volume (<1.4 mL) may indicate retrograde ejaculation (sperm going backward into the bladder), ejaculatory duct obstruction, or seminal vesicle dysfunction. Very low volume should prompt urinalysis after ejaculation (post-ejaculate urinalysis) to check for retrograde ejaculation.
pH Semen is normally alkaline (pH >7.2) due to secretions from the seminal vesicles. Low pH combined with low volume and azoospermia suggests ejaculatory duct obstruction or absent seminal vesicles (as seen in CFTR mutations).
Vitality (Live Sperm) Measured by dye exclusion or hypoosmotic swelling test. Vitality below 54% (necrospermia) in combination with low motility suggests dead or dying sperm — which may reflect epididymal dysfunction, oxidative stress, or antibody attachment.
Leukocytes White blood cells >1 million/mL (leukocytospermia) indicate genital tract inflammation or infection — a treatable cause of elevated oxidative stress and elevated sperm DNA fragmentation. Requires culture and targeted antibiotic treatment.
Semen Analysis Terminology Reference
| Term | Definition |
|---|---|
| Normozoospermia | All parameters within WHO 2021 reference limits |
| Oligospermia | Concentration <16 million/mL |
| Severe oligospermia | Concentration <5 million/mL |
| Cryptozoospermia | Sperm present only after centrifugation |
| Azoospermia | No sperm in ejaculate on two confirmed samples |
| Asthenospermia | Progressive motility <30% |
| Teratospermia | Normal morphology <4% |
| Oligoasthenoteratospermia (OAT) | All three parameters below reference |
| Necrospermia | Vitality <54% (most sperm non-viable) |
| Hypospermia | Volume <1.4 mL |
| Leukocytospermia | WBC >1 million/mL |
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The Hormonal Panel
When semen analysis is abnormal — especially with low sperm count or azoospermia — a hormonal evaluation helps identify whether the problem is in the testicle itself (primary testicular failure) or in the signaling cascade from the brain (secondary/hypogonadotropic hypogonadism).
Standard Male Fertility Hormonal Panel
| Hormone | Normal Range (approximate) | Interpretation |
|---|---|---|
| FSH | 1.5–12.4 mIU/mL | Elevated in primary testicular failure; suppressed in hypogonadotropic hypogonadism or TRT |
| LH | 1.7–8.6 mIU/mL | Mirrors FSH; elevated in primary failure, low in central cause |
| Total testosterone | 300–1000 ng/dL | Low suggests hypogonadism; interpret with LH/FSH to determine cause |
| Free testosterone | 5–21 ng/dL | More clinically meaningful in obese men (SHBG-bound T is unavailable) |
| Estradiol | 10–40 pg/mL | Elevated in obese men; high E2 suppresses HPG axis |
| Prolactin | <18 ng/mL | Elevated = hyperprolactinemia; MRI pituitary if >100 |
Interpreting FSH in Azoospermia:
FSH level is the single most clinically important hormone in the azoospermic male:
- High FSH + azoospermia: Primary testicular failure (non-obstructive azoospermia) — the testicle is not producing sperm despite normal pituitary signaling. Testicular biopsy or surgical sperm retrieval (micro-TESE) may be needed.
- Low/normal FSH + azoospermia: May indicate obstructive azoospermia (tubes blocked but testicle produces sperm) or hypogonadotropic hypogonadism. Both are potentially treatable.
- Normal FSH + oligospermia: Often seen with varicocele, genetic causes, or idiopathic subfertility.
Genetic Testing
Genetic evaluation is recommended when semen analysis shows severe oligospermia (<5 million/mL), azoospermia, or when there is a family history of genetic disease or recurrent pregnancy loss.
Karyotype (Chromosomal Analysis)
A standard 46,XY karyotype confirms normal chromosomal complement. Abnormalities found in azoospermic and severely oligospermic men include:
- Klinefelter syndrome (47,XXY): The most common chromosomal cause of male infertility, found in ~15% of azoospermic men. An extra X chromosome disrupts spermatogenesis. Many men with mosaic Klinefelter (46,XY/47,XXY) retain focal areas of spermatogenesis accessible by micro-TESE.
- Robertsonian translocations: Fusion of two acrocentric chromosomes. Carriers may have subfertility and produce unbalanced embryos; PGT-A is important when proceeding to IVF.
- Structural chromosomal rearrangements: Inversions and translocations that impair meiosis.
Y-Chromosome Microdeletion Testing
The long arm of the Y chromosome contains the AZF (azoospermia factor) region, which is critical for spermatogenesis. Deletions in this region are found in ~15% of azoospermic and ~7% of severely oligospermic men.
| Deletion | Location | Clinical Significance |
|---|---|---|
| AZFa deletion | Proximal | Sertoli cell-only syndrome — no sperm retrievable by any method |
| AZFb deletion | Middle | Spermatogenic arrest — sperm retrieval usually fails |
| AZFc deletion | Distal | Most common; variable phenotype — sperm often retrievable by micro-TESE |
| AZFbc deletion | b + c region | Sperm retrieval generally fails |
Y-microdeletion testing is essential before surgical sperm retrieval because AZFa and AZFb deletions predict near-zero retrieval success, sparing patients from unnecessary surgery. AZFc deletions are passed from father to son in any assisted reproduction using Y-bearing sperm — important for genetic counseling.
CFTR Gene Testing (Cystic Fibrosis Transmembrane Conductance Regulator)
Men with congenital bilateral absence of the vas deferens (CBAVD) — a cause of obstructive azoospermia — almost always carry at least one CFTR mutation. CFTR mutation testing is mandatory before sperm retrieval in CBAVD because:
- The female partner must also be tested — if both are carriers, offspring have a 25% risk of cystic fibrosis
- PGT-M (preimplantation genetic testing) may be indicated before embryo transfer
CFTR mutations are also found in men with normal vas deferens but unexplained obstructive azoospermia — testing is recommended in this group as well.
Sperm DNA Fragmentation Testing
The semen analysis evaluates the envelope of the sperm (count, motility, shape) but not the quality of the genetic material inside. Sperm DNA fragmentation (DFI) measures the percentage of sperm with DNA strand breaks.
DFI >25% is associated with:
- Reduced natural conception rates
- Higher miscarriage rates
- Poorer IVF/ICSI embryo development and live birth rates
DFI testing is recommended for men with unexplained infertility, recurrent pregnancy loss, or recurrent IVF failure — especially when standard semen parameters appear normal. See the dedicated sperm DNA fragmentation guide for full details on testing methods, causes, and treatment. Men with consistently normal semen analyses but unexplained fertility challenges should also review the unexplained infertility hub for a broader diagnostic perspective.
Testicular Ultrasound
A scrotal/testicular ultrasound evaluates testicular size, echogenicity (texture), and blood flow, and assesses for:
- Varicocele: Dilated veins >3 mm with Doppler-confirmed reflux — the most common treatable cause of male infertility
- Testicular mass or microlithiasis: Rare but important finding; testicular germ cell tumors are more common in infertile men
- Epididymal cysts or dilation: Suggests epididymal obstruction (obstructive azoospermia)
- Testicular atrophy: Volume <12 mL suggests primary testicular failure
- Absent epididymis or vas deferens: Confirms CBAVD diagnosis
Testicular ultrasound is recommended as part of the initial workup in men with azoospermia, severe oligospermia, or when varicocele is suspected on clinical exam.
Post-Ejaculate Urinalysis (PEUA)
In men with very low semen volume (<1.0 mL) and/or suspected retrograde ejaculation, a urine sample is collected immediately after ejaculation. Finding sperm in the post-ejaculate urine confirms retrograde ejaculation — a treatable cause of male infertility. Causes include:
- Prior bladder neck or transurethral resection surgery
- Diabetes-related autonomic neuropathy
- Alpha-blocker or antihypertensive medication use
- Spinal cord injury
Treatment with alpha-agonist medications (pseudoephedrine, imipramine) or sperm retrieval from centrifuged post-ejaculate urine are both options.
When to See a Reproductive Urologist
A reproductive urologist (or male infertility specialist) should be consulted when:
- Semen analysis shows azoospermia (zero sperm) on two confirmed samples
- Severe oligospermia (<5 million/mL) on two confirmed samples
- Abnormal hormonal panel (high FSH, low testosterone)
- Suspected varicocele on physical exam or ultrasound
- Prior vasectomy with desire for reversal or sperm retrieval
- Genetic testing reveals Y-microdeletion or karyotype abnormality
- Suspected obstructive cause (low volume, normal FSH, history of prior surgery or infection)
- Persistent leukocytospermia requiring workup and treatment
The evaluation by a reproductive urologist includes physical examination of the scrotum, testes, vas deferens, and epididymis — information not available from laboratory tests alone.
Male Fertility Testing: A Practical Timeline
For most couples beginning fertility evaluation, male testing can begin simultaneously with the female evaluation — there is no reason to "wait and see" on the male side. When both partners need evaluation, knowing what to expect at your first fertility clinic appointment can ease the process.
| Visit | Tests |
|---|---|
| Initial evaluation | Semen analysis x2 (4–6 weeks apart if first is abnormal) |
| If SA abnormal | FSH, LH, testosterone, prolactin, estradiol |
| If low count or azoospermia | Karyotype, Y-microdeletion, CFTR (if indicated) |
| If azoospermia confirmed | Testicular ultrasound, referral to reproductive urologist |
| If recurrent loss or unexplained infertility with normal SA | Sperm DNA fragmentation (DFI) |
| If low volume | Post-ejaculate urinalysis |
Frequently Asked Questions
Q: What are the WHO 2021 reference values for a normal semen analysis? A: The WHO 2021 (6th edition) lower reference limits — representing the 5th percentile of men whose partners conceived within 12 months — are: sperm concentration above 16 million/mL, total sperm count above 39 million per ejaculate, progressive motility above 30%, total motility above 42%, normal morphology (Kruger strict criteria) above 4%, and sperm vitality above 54%. Volume below 1.4 mL and pH below 7.2 are also flagged.
Q: How important is FSH level in evaluating azoospermia? A: FSH is the most clinically important hormone in azoospermic men. Elevated FSH combined with azoospermia suggests primary testicular failure (non-obstructive azoospermia), where the testicle is not producing sperm despite normal pituitary signaling. Low or normal FSH with azoospermia may indicate obstructive azoospermia (tubes blocked but the testicle produces sperm) or hypogonadotropic hypogonadism — both potentially treatable conditions.
Q: Why is Y-microdeletion testing important before surgical sperm retrieval? A: Y-microdeletion testing is essential because specific deletion locations predict whether sperm can be retrieved at all. AZFa deletions cause Sertoli cell-only syndrome, and AZFb deletions cause spermatogenic arrest — both predict near-zero retrieval success, sparing patients from unnecessary surgery. AZFc deletions, the most common type, have variable outcomes and sperm are often retrievable by micro-TESE. Y-microdeletions are also passed to sons in assisted reproduction.
Q: What does sperm DNA fragmentation measure and when should it be tested? A: Sperm DNA fragmentation (DFI) measures the percentage of sperm with DNA strand breaks — information not captured by the standard semen analysis, which only evaluates count, motility, and shape. DFI above 25% is associated with reduced natural conception rates, higher miscarriage rates, and poorer IVF/ICSI embryo development and live birth rates. Testing is recommended for men with unexplained infertility, recurrent pregnancy loss, or recurrent IVF failure, particularly when standard semen parameters appear normal.
Q: Should male and female fertility testing happen at the same time? A: Yes — male testing should begin simultaneously with female evaluation. There is no clinical reason to defer the semen analysis, and male factor infertility is identified in approximately 40–50% of all couples with difficulty conceiving. A semen analysis is also one of the simplest and least expensive fertility tests available, making early evaluation both practical and efficient.
Key Takeaways
- The semen analysis is the cornerstone of male fertility testing — always confirm an abnormal result with a second sample
- WHO 2021 reference values: concentration >16 million/mL, total motility >42%, progressive motility >30%, morphology >4%
- FSH level is the critical hormone in azoospermia — elevated FSH suggests primary testicular failure; low FSH suggests a central (treatable) cause
- Y-microdeletion testing is mandatory before surgical sperm retrieval — AZFa/b deletions predict zero retrieval success
- CFTR testing is essential in congenital bilateral absence of the vas deferens
- Sperm DNA fragmentation testing complements the standard semen analysis and should be ordered for unexplained infertility or recurrent loss
- Testicular ultrasound detects varicocele, atrophy, and other structural causes of male infertility
References
- World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen, 6th edition. WHO Press; 2021.
- American Society for Reproductive Medicine (ASRM). Diagnostic evaluation of the infertile male: a committee opinion. Fertil Steril. 2015;103(3):e18–e25.
- Esteves SC, Miyaoka R, Agarwal A. An update on the clinical assessment of the infertile male. Clinics (Sao Paulo). 2011;66(4):691–700.
- Reijo R, Lee TY, Salo P, et al. Diverse spermatogenic defects in humans caused by Y chromosome deletions encompassing a novel RNA-binding protein gene. Nat Genet. 1995;10(4):383–393.
This article is for informational purposes only and does not constitute medical advice. Consult a board-certified reproductive urologist for a complete male fertility evaluation.
