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Semen Analysis

The evaluation of the potentially infertile male initially involves screening with semen analyses, followed by further examination when warranted semen analysis, semen test, semen analysis, seamen analysis, sperm test. However, normal semen results do not exclude male causes of the couple's infertility.

Several semen analyses, obtained by masturbation after abstinence for the man's usual ejaculatory interval, are required to begin the male evaluation. These samples should be obtained over a 75- to 90-day interval to evaluate the inherent long-term variability in semen measures. Normal semen parameters include a sperm concentration greater than 20 million/mL with at least 2 mL of semen.

Additional tests are selectively used in the evaluation of the potentially infertile male when the history, physical examination, or semen analyses suggest or disclose abnormalities. These include biochemical evaluation of semen for markers from accessory glands or spermatozoal enzymes; serum levels of gonadotropins, prolactin, and sex steroids; scrotal Doppler ultrasound examination for varicocele; seminal fluid cultures for Mycoplasma, Ureaplasma, and Chlamydia species; testicular biopsy; retrograde vasography; computerized videomicrographic analysis of sperm motion; and blood karyotype.

Sperm antibody testing is indicated 1) when an immunologic cause of male infertility is suspected from other studies (eg, the presence of significant agglutination on semen analysis), an abnormal postcoital test, or in vitro sperm-cervical mucus contact tests; 2) when abnormal sperm function is identified as determined by sperm penetration test, hemizona assay, or failed fertilization during IVF; or 3) in cases of unexplained infertility. Antisperm antibodies may be detected either in the semen.

Table 7. Potential Causes of Isolated Semen Abnormalities
Semen Abnormality	Potential Causes
Low sperm concentration	Idiopathic Endocrine dysfunction including androgen receptor defects Varicocele Germinal epithelial dysfunction/failure
Low semen volume	Inappropriate collection Idiopathic Ductal obstruction or atresia Destruction or dysfunction of the seminal vesicles or prostate Retrograde ejaculation
Low sperm motility	Varicocele Infection Idiopathic Antisperm antibodies Epididymal dysfunction Medication, tobacco, or marijuana use Environmental toxins Endocrine dysfunction including androgen receptor defects Infrequent ejaculation Ultrastructural ciliary defects (Kartagener's syndrome)
Low normal sperm morphology	Idiopathic Varicocele Endocrine dysfunction including androgen receptor defects

Evaluation of Sperm Function

Additional studies may be selectively used to further evaluate sperm transport in the female reproductive tract, sperm capacitation and acrosome reaction, zona pellucida binding, sperm-egg fusion and penetration, and sperm decondensation within the oocyte cytoplasm. Sperm transport is initially assessed by the postcoital test, with additional in vitro tests of sperm-mucus interaction to further characterize the abnormality detected on the postcoital test. Sperm-mucus interaction can be assessed by examination of sperm penetration through a mucus interface under the microscope and crossed-hostility tests with donor mucus. The zona-free hamster oocyte penetration test evaluates the ability of a sperm population to capacitate, acrosome-react, bind, and penetrate the oocyte membrane and decondense within the ooplasm. Especially when conducted with acroso-mal stimulants.

The first contact between sperm and oocyte involving specific surface receptors is at the zona pellucida, an important site not assessed by the sperm penetration assay. The hemizona assay is used to evaluate this sperm-zona pellucida interaction. Human oocytes are microbisected to obtain two matched, half (hemi) zona surfaces, and the ooplasm is discarded.