Semen Analysis

Semen analysis is a simple, inexpensive, and reasonably definitive test that's used in a broad range of applications, including evaluation of a man's fertility. Fertility analysis usually includes measuring the volume of seminal fluid, performing sperm counts, and microscopic examination of spermatozoa. Sperm are counted in much the same way that white blood cells, red blood cells, and platelets are counted on an anticoagulated blood sample. Motility and morphology are studied microscopically after staining a drop of semen.

If analysis detects an abnormality, additional tests (for example, liver, thyroid, pituitary, or adrenal function tests) may be performed to identify the underlying cause and to screen for metabolic abnormalities (such as diabetes mellitus). Significant abnormalities - such as greatly decreased sperm count or motility, or marked increase in morphologically abnormal forms ­may require testicular biopsy.

Purpose

• To evaluate male fertility in an infertile couple
• To substantiate the effectiveness of vasectomy
• To detect semen on the body or clothing of a suspected rape victim or elsewhere at the crime scene
• To identify blood group substances to exonerate or incriminate a criminal suspect
• To rule out paternity on grounds of complete sterility

Patient preparation

Evaluation of fertility

• Provide written instructions, and inform the patient that the most desirable specimen requires masturbation, ideally in a doctor's office or a laboratory.
• Tell him to follow the instructions given to him regarding the period of sexual continence before the test because this may increase his sperm count. Some doctors specify a fixed number of days, usually between 2 and 5; others advise a period of continence equal to the usual interval between episodes of sexual intercourse.
• If the patient prefers to collect the specimen at home, emphasize the importance of delivering the specimen to the laboratory within 3 hours after collection. Warn him not to expose the specimen to extreme temperatures or to direct sunlight (which can also increase its temperature). Ideally, the specimen should remain at body temperature until liquefaction is complete (about 20 minutes). To deliver a semen specimen during cold weather, suggest that the patient keep the specimen container in a coat pocket on the way to the laboratory to protect the specimen from exposure to cold.
• Alternatives to collection by masturbation include coitus interruptus or the use of a condom. For collection by coitus interruptus, instruct the patient to withdraw immediately before ejaculation and to deposit the ejaculate in a suitable specimen container. For collection by condom, tell the patient to first wash the condom with soap and water, rinse it thoroughly, and allow it to dry completely. (powders or lubricants applied to the condom may be spermicidal.) After collection, instruct him to tie the condom, place it in a glass jar, and promptly deliver it to the laboratory.
• Fertility may also be determined by collecting semen from the woman after coitus to assess the ability of the spermatozoa to penetrate the cervical mucus and remain active. For the postcoital cervical mucus test, instruct the patient to report for examination during the ovulatory phase of her menstrual cycle, as determined by basal temperature records, and as soon as possible after sexual intercourse (within 8 hours). Explain to the patient scheduled for this test that the procedure takes only a few minutes. Tell her that she'll be placed in the lithotomy position and that a speculum will be inserted into the vagina to collect the specimen. She may feel some pressure but no pain during this procedure.

Semen collection from rape victim

• Explain to the patient that the examiner will try to obtain a semen specimen from her vagina.
• Prepare her for insertion of the speculum as you would the patient scheduled for postcoital examination.
• Handle the victim's clothes as little as possible. If her clothes are moist, put them in a paper bag - not a plastic bag (which causes seminal stains and secretions to mold). Label the bag properly, and send it to the laboratory immediately.
• Provide emotional support by speaking to the patient calmly and reassuringly. Encourage her to express her fears and anxieties. Listen sympathetically.
• If she's scheduled for vaginal lavage, tell the rape victim to expect a cold sensation when saline solution is instilled to wash out the specimen.
• Help her relax during this procedure by instructing her to breathe deeply and slowly through her mouth.
• Instruct the victim to urinate just before the test, but warn her not to wipe the vulva afterward because this may remove semen.

Equipment

For semen collection by masturbation, coitus interruptus, or condom: clean plastic specimen container (for example, disposable urine or sputum container with lid)

For semen collection from rape victim: clean plastic specimen container, vaginal speculum, rubber gloves, cotton applicator sticks, glass microscopic slides with frosted ends, physiologic (0.85%) saline solution, Pap sticks, jars containing 95% ethanol, large syringe, rubber bulb or other device suitable for vaginal lavage

For a postcoital specimen collection: clean plastic specimen container, vaginal speculum, rubber gloves, cotton applicator sticks, glass microscopic slides with frosted ends, 1-ml tuberculin syringe without a cannula or needle

Procedure and posttest care

• Obtain a semen specimen for a fertility study by asking the patient to collect semen in a clean plastic specimen container.
• A specimen is obtained from the vagina of a rape victim by direct aspiration, saline lavage, or a direct smear of vaginal contents, using a Pap stick or, less desirably, a cotton applicator stick. Dried smears are usually collected from the suspected rape victim's skin by gently washing the skin with a small piece of gauze moistened with physiologic saline solution.
• Prepare direct smears on glass microscopic slides after labeling the frosted end. Immediately place smeared slides in Coplin jars containing 95% ethanol.
• Before postcoital examination, the examiner wipes any excess mucus from the external cervix and collects the specimen by direct aspiration of the cervical canal, using a 1-ml tuberculin syringe without a cannula or needle.
• Inform a patient who is undergoing infertility studies that test results should be available in 24 hours.
• Refer the suspected rape victim to an appropriate specialist for counseling ­a gynecologist, psychiatrist, clinical psychologist, nursing specialist, member of the clergy, or representative of a community support group, such as Women Organized Against Rape (WOAR).

Precautions

• If the patient prefers to collect the specimen during coitus interruptus, tell him he must prevent any loss of semen during ejaculation.
• Deliver all specimens, regardless of source or method of collection, to the laboratory promptly.
• Protect semen specimens for fertility studies from extremes of temperature and direct sunlight during delivery to the laboratory.
• Never lubricate the vaginal speculum. Oil or grease hinders examination of spermatozoa by interfering with smear preparation and staining and by inhibiting sperm motility through toxic ingredients. Instead, moisten the speculum with water or physiologic saline solution.
• Use extreme caution in securing, labeling, and delivering all specimens to be used for medicolegal purposes. You may be asked to testify as to when, where, and from whom the specimen was obtained; the specimen's general appearance and identifying features; steps taken to ensure the specimen's integrity; and when, where, and to whom the specimen was delivered for analysis. If your hospital or clinic uses routing slips for such specimens, fill them out carefully, and place them in the permanent medicolegal file.

Normal Findings

Normal semen volume is greater than or equal to 2 ml. Paradoxically, the semen volume of many men in infertile couples is increased. Abstinence for 1 week or more results in progressively increased semen volume. (With abstinence of up to 10 days, sperm counts increase, sperm motility progressively decreases, and sperm morphology stays the same.) Liquefied semen is generally highly viscid, translucent, and gray-white, with a musty or acrid odor. After liquefaction, specimens of normal viscosity can be poured in drops. Normally, semen is slightly alkaline, with a pH of 7.2 to 8.

Other normal characteristics of semen: It coagulates immediately and liquefies within 20 minutes; the normal sperm count is 20 million/ml or more; 30% of spermatozoa have normal morphology; and 50% or more of spermatozoa show progressive motility within 4 hours of collection.

The normal postcoital cervical mucus test shows at least 10 motile spermatozoa per microscopic high-power field and spinnbarkeit (a measurement of the tenacity of the mucus) of at least 4" (10 cm). These findings indicate adequate spermatozoa and receptivity of the cervical mucus.

Abnormal findings

Abnormal semen is not synonymous with infertility. Only one viable spermatozoon is needed to fertilize an ovum. Although a normal sperm count is 20 million/ml or more, many men with sperm counts below 1 million/ml have fathered normal children. Only men who can't deliver any viable spermatozoa in their ejaculate during sexual intercourse are absolutely sterile.

Nevertheless, subnormal sperm counts, decreased sperm motility, and abnormal morphology are usually associated with decreased fertility.

Other tests may be necessary to evaluate the patients's general health, metabolic satus, or the function of specific endocrine glands (pituitary, thyroid, adrenal, or gonadal).

Interfering factors

• Poor timing of test within the menstrual cycle (abnormal postcoital test results)
• Prior cervical conization or cryotherapy and some medications, such as clomiphene citrate (possible abnormal postcoital test result due to changes in cervical mucus).
• Delayed transport of the specimen, exposure to extreme temperatures or direct sunlight, or the presence of toxic chemicals in the container or the condom (possible decrease in number of viable sperm)
• An incomplete specimen- for example, from coitus interrupts or improper collection technique (decrease in specimen volume)