Semen Analysis

Semen analysis measures the volume and physical properties of the ejaculate, the concentration, motility and morphology of the spermatozoa, and the presence of white cells and antibodies. It is the first test in the evaluation of male infertility and the check of vasectomy success. It describes sperm production, transport, and accessory gland function, but does not prove fertility or infertility, since there is overlap between the results of fertile and subfertile men.

About 15% of couples are unable to conceive after 12 months of trying, and a male factor is the sole cause in about 20 to 30% and a contributor in another 20 to 30% of these couples. Male factor infertility has causes including varicocele (about 35 to 40% of primary infertility), obstruction, genetic and endocrine disorders, infections, drugs, heat, and lifestyle.

Indications. Infertility investigation for the couple (after 12 months, or sooner if the woman is over 35 years or risk factors are present), post-vasectomy check, before assisted reproduction, hypogonadism, testicular disease, varicocele, history of cryptorchidism, chemotherapy or radiotherapy (including sperm banking), suspected ejaculatory dysfunction, and medicolegal assessment.

Specimen. Collected by masturbation into a wide mouthed sterile container after 2 to 7 days of abstinence (ideally 2 to 3 days, with the same period each time). Do not use lubricants, condoms (except special non-spermicidal ones) or saliva. Keep at body temperature, and deliver to the laboratory within 30 to 60 minutes. Record the abstinence period, collection completeness (especially the first fraction, which holds most sperm), time of collection, and medicines. Two or three samples, at least 2 to 4 weeks apart, are needed, since variation is large.

Lower reference limits (fifth percentile) for fertile men.

Values under these limits do not define infertility, and values over them do not guarantee fertility.

Terminology.

• Normozoospermia: all values within the reference range.
• Oligozoospermia: low concentration. Azoospermia: no sperm in the ejaculate after centrifugation. Cryptozoospermia: sperm only after centrifugation.
• Asthenozoospermia: low motility. Teratozoospermia: low normal forms. Combined terms such as oligoasthenoteratozoospermia are used.
• Aspermia: no ejaculate. Necrozoospermia: all sperm are dead. Leucocytospermia: white cells over 1 million/mL.

Interpretation by pattern.

• Azoospermia with low volume (under 1.0 mL) and acidic pH (under 7.2) and low fructose: ejaculatory duct obstruction or congenital bilateral absence of the vas deferens (associated with CFTR variants).
• Azoospermia with normal volume, small testes and high FSH (over twice normal): non-obstructive testicular failure (Klinefelter syndrome, Y chromosome microdeletions, cryptorchidism, chemotherapy, mumps orchitis).
• Azoospermia with normal volume, normal testes and normal FSH: obstructive, such as post-infective or post-vasectomy.
• Azoospermia with low FSH, LH and testosterone: hypogonadotropic hypogonadism (pituitary disease, Kallmann syndrome, anabolic steroid use), which is treatable.
• Low volume with a normal count: incomplete collection, retrograde ejaculation (post-void urine contains sperm), androgen deficiency.
• Oligozoospermia with asthenozoospermia and teratozoospermia: varicocele, heat, drugs, infection, smoking, obesity, and idiopathic.
• Isolated asthenozoospermia: epididymal disease, antisperm antibodies, ciliary defects (Kartagener syndrome), infection.
• Agglutination: suggests antisperm antibodies (confirm with the mixed antiglobulin reaction test).
• Leucocytospermia over 1 million/mL: genital tract infection or inflammation, and cultures for Chlamydia, gonorrhoea, Ureaplasma and other organisms.

Post-vasectomy. Clearance is declared when no sperm are seen on a sample 12 weeks or 20 ejaculations after the procedure. Rare non-motile sperm (under 100 000/mL) may be accepted in some practices. Motile sperm after 3 months indicate failure or recanalisation.

Additional tests. Sperm DNA fragmentation, antisperm antibodies, oxidative stress markers, seminal fructose (low in ejaculatory duct obstruction), post-ejaculatory urinalysis (retrograde ejaculation), and functional tests of fertilising ability. They are used selectively.

Critical values and findings needing immediate action.

• Azoospermia or severe oligozoospermia (under 5 million/mL): endocrine tests, karyotype and Y microdeletion analysis, and urgent referral for fertility planning.
• Azoospermia with a testicular mass or pain: scrotal ultrasound for testicular cancer.
• Low testosterone with raised prolactin or low gonadotropins: pituitary imaging.
• Before cancer treatment: sperm cryopreservation must be offered before chemotherapy or radiotherapy begins.
• Motile sperm after a vasectomy: contraception continues, and the result is repeated.

Interferences and pitfalls.

• Variation between samples is large, and one abnormal result is repeated after at least 2 to 4 weeks (and sooner for azoospermia).
• Recent fever or illness depresses counts for up to 3 months (a spermatogenesis cycle takes about 74 days).
• Incomplete collections, poor technique, wrong container, cold exposure and delays give false results.
• Abstinence under 2 days lowers volume and count, and over 7 days lowers motility.
• Condoms, lubricants and saliva reduce motility.
• Laboratory quality varies, with subjective counts in morphology and motility. Laboratories should use quality control.
• Drugs that lower sperm quality: testosterone and anabolic steroids (suppress spermatogenesis), sulfasalazine, nitrofurantoin, finasteride, methotrexate, chemotherapy, and cannabis.
• Reference limits come from fertile men and are not diagnostic thresholds.
• A normal analysis does not exclude sperm dysfunction, and the female partner must be assessed at the same time.

Special groups.

• Men over 40 years: gradual decline in quality, with increased DNA damage.
• Cancer patients: sperm banking before treatment, and semen quality may be poor already.
• Spinal cord injury and diabetes: ejaculatory dysfunction and retrograde ejaculation.
• Men on testosterone replacement or anabolic steroids: azoospermia is common and reversible in many.
• Regions: untreated genital infections (gonorrhoea, chlamydia, tuberculosis and schistosomiasis) cause obstruction, and delayed diagnosis is common.

Follow up tests. Repeat semen analysis, FSH, LH, testosterone and prolactin, karyotype, Y chromosome microdeletion analysis and CFTR testing in azoospermia or severe oligozoospermia, scrotal ultrasound, transrectal ultrasound, post-ejaculatory urine, semen culture, urine for Chlamydia and gonorrhoea, antisperm antibodies, sperm DNA fragmentation, and testicular biopsy with sperm retrieval for assisted reproduction.