Semen Analysis (Sperm Count, Sperm Examination, Seminal Cytology, Semen Examination): Overview, Indication, Normal Values by Nurses Note

Semen Analysis (Sperm Count, Sperm Examination, Seminal Cytology, Semen Examination) 

INDICATIONS OF SEMEN ANALYSIS

Semen analysis is used to evaluate the quality of sperm, to evaluate an infertile couple, and to document the adequacy of operative vasectomy. 

TEST EXPLANATION OF SEMEN ANALYSIS

Semen production depends on the function of the testicles; semen analysis is a measure of testicular function. Gonadotropin-releasing hormone (Gn-RH) stimulates the pituitary to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH, also called interstitial cell–stimulating hormone). The FSH stimulates the Sertoli cell growth to encourage sperm production. LH stimulates the Leydig cells to produce testosterone, which in turn stimulates the semi-niferous tubules to produce sperm. Inadequate sperm production can be the result of primary gonadal failure (because of age, genetic cause [Klinefelter syndrome], infection, radiation, or surgical orchiectomy) or secondary gonadal failure (because of pituitary diseases). These forms of gonadal failure can be differentiated by measuring LH and FSH levels. In primary gonadal failure, LH and FSH levels are increased. In secondary gonadal failure, they are decreased. Stimulation tests using Gn-RH agonists such as leuprolide acetate clomiphene, or human chorionic gonadotropin are also used in the differentiation. Men with aspermia (no sperm) or oligospermia (<20 million/mL) should be evaluated endocrinologically for pituitary, thyroid, or testicular aberrations.

Semen analysis is one of the most important aspects of the fertility workup because the cause of a couple’s inability to conceive often lies with the man. After 2 to 3 days of sexual abstinence, semen is collected and examined for volume, sperm count, motility, and morphology. 

The freshly collected semen is first measured for volume, pH, viscosity. After liquefaction of the white, gelatinous ejaculate, a sperm count is done. Men with very low or very high counts likely are infertile. The motility of the sperm is then evaluated; at least 50% should show rapid (>25 μm/s at  37°C) or sluggish progressive motility. Morphology is studied by staining a semen preparation and calculating the number of sperm with normal versus abnormal morphology. Using the Kruger criteria, sperm morphology must be greater than 14% to be considered normal. Morphology of less than 4% is associated with severe infertility. More exhaustive semen analysis or second-tier testing for male infertility may include sperm functional testing, identification of sperm antibodies and biochemical testing.

Sperm functional tests include:

  1. Sperm/cervical mucus interaction. his is a postcoital test that evaluates the sperm/cervical mucus interaction. Normal is more than 10–20 motile sperm per high power field. 

 2. Computer-assisted semen analysis. In this test, several different sperm kinetics are evaluated including velocities, linearity, and amplitude of sperm head displacement. 

 3. Sperm penetration assay (SPA). his is a multistep laboratory test that offers a biologic assessment of several aspects of human sperm fertilizing ability. 

 4. Hemizona and zona pellucida binding tests. These include the hemizona assay (HZA) and a competitive intact zona binding assay. These tests evaluate the interaction between the spermatozoa and the zona pellucida of the female egg. These tests thereby evaluate many functions of the sperm at one time.

Interruption in sperm DNA integrity is a potential cause of male infertility. Although sperm with fragmented DNA may be able to fertilize oocytes, subsequent embryo and fetal development may be impaired. DNA fragmentation in sperm increases with age. Therefore impaired DNA integrity may be an increasing infertility factor among older couples. Testing for DNA integrity includes sperm chromatin structure assay test and the sperm DNA fragmentation assay (SDFA) test. the sperm specimen is considered abnormal if more than 70% of the sperm have abnormal forms. There are several other direct and indirect tests of DNA damage and chromosomal tests measuring chromosomal numerical abnormalities in sperm. 

Sperm biochemical testing includes the measurement of zinc, citric acid, glucosidase and the hyaluronan binding assay (HBA). The HBA is based on the ability of mature, but not immature, sperm to bind to hyaluronan, the main mucopolysaccharide of the egg matrix and a component of human follicular fluid. Hyaluronan-binding capacity is acquired late in the sperm maturation process; immature sperm lack this ability. Therefore a low level of sperm binding to hyaluronan suggests that there is a low proportion of mature sperm in the sample. Similar to the sperm penetration assay, it has been suggested that the HBA assay may be used to determine the need for an intracytoplasmic sperm injection procedure as part of an assisted reproductive technique. 

A single sperm analysis, especially if it indicates infertility, is inconclusive because sperm count varies from day to day. A semen analysis should be done at least twice and possibly a third time, 3 weeks apart. A normal semen analysis alone does not accurately assess the male factor unless the effect of the partner’s cervical secretion on sperm survival is also determined. Sperm antibody testing is also performed on the specimen. 

In addition to its value in infertility workups, semen analysis is also helpful in documenting adequate sterilization after a vasectomy. It is usually performed 6 weeks after the surgery. If any sperm are seen, the adequacy of the vasectomy must be suspect.

NORMAL FINDINGS OF SEMEN ANALYSIS

Volume: 2–5 mL 

Liquefaction time: 20–30 minutes after collection

 Appearance: Normal

 Motile/mL: ≥10 × 106 

Sperm/mL: ≥20 × 106

Viscosity: ≥3 

Agglutination: ≥3 

Supravital: ≥75% live 

Fructose: Positive 

pH: 7.12–8 

Sperm count (density): ≥20 million/mL

Sperm motility: ≥50% at 1 hour 

Sperm morphology: >30% (Kruger criteria >14%) normally shaped

INTERFERING FACTORS OF SEMEN ANALYSIS

 Drugs that may cause decreased sperm counts include antineoplastic agents (eg, methotrexate), cimetidine, estrogens, and methyltestosterone.

Clinical Priorities

• It is best to collect the semen for this test after 2 to 3 days of sexual abstinence. 

 • For best results the semen specimen should be collected in the physician’s office by masturbation. 

 • A single sperm analysis is inconclusive because the sperm count varies from day to day. A semen analysis should be done two or three times for the best results. 

PROCEDURE AND PATIENT CARE OF SEMEN ANALYSIS

 Before

  • Explain the procedure to the patient. 

 •  Instruct the patient to abstain from sexual activity for 2 to 3 days before collecting the specimen.

 •  Prolonged abstinence before the collection should be discouraged, because the quality of the sperm cells, and especially their motility, may diminish. 

 • Give the patient the proper container for the semen collection. 

 •  Instruct the patient to avoid alcoholic beverages for several days before the collection.

  •  For evaluation of the adequacy of vasectomy, the patient should ejaculate once or twice before the day of examination to clear the distal portion of the vas deferens.

During 

 • Note that semen is best collected by ejaculation into a clean container. For best results, the specimen should be collected in the physician’s office or laboratory by masturbation. 

 • Note that less satisfactory specimens can be obtained in the patient’s home by coitus interruptus or masturbation. Note the following procedural steps: 

 1. Instruct the patient to deliver these home specimens to the laboratory within 1 hour after collection. 2. Tell the patient to avoid excessive heat and cold during the transportation of the specimen.

After 

 • Record the date of the previous semen emission along with the collection time and date of the fresh specimen. 

 • Tell the patient when and how to obtain the test results. Remember that abnormal results may have a devastating effect on the patient’s sexuality.

TEST RESULTS AND CLINICAL SIGNIFICANCE OF SEMEN ANALYSIS

Infertility: One of the most common causes of infertility is inadequate sperm production. 

Vasectomy (obstruction of vas deferens): Semen analysis is necessary before vasectomy can be considered to be adequate. 

Orchitis: This is usually caused by a virus (varicella) or rarely by a bacterium. 

Testicular failure: This can be congenital (Klinefelter syndrome) or acquired (eg, infection). Usually, with acquired forms of testicular failure, sperm are present but in low quantities. With congenital forms of testicular failure, no sperm are seen. 

Hyperpyrexia, Varicocele: A common finding in sperm analysis is called “stress pattern.” this is said to exist when greater than 20% of the sperm have the abnormal appearance and sperm counts are low. The stress pattern indicates presence of a varicocele or recent febrile illness. 

Pituitary pathologic condition (adenoma, infarction): this causes hypospermia because of reduced or absent LH and FSH levels. As a result, spermatogenesis does not occur.