 | Infertility |
| Infertility: Testing | |||||||||||
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Semen Analysis
The cornerstone of testing for a male infertility evaluation is the semen analysis. It is important that the semen analysis be performed properly by an andrology (male reproduction) laboratory experienced in handing poor quality semen samples. Standards for testing on a semen sample have been established by the World Health Organization (WHO). A semen analysis should include the following information:
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A minimum of 2 semen samples is necessary in order to exclude biologic variation, fluctuation in samples due to collection technique, and changes due to varying length of abstinence.
It is preferred that the semen sample be collected by masturbation and be promptly delivered to the laboratory (within 1 - 1½ hours). The sample should be kept at body temperature and should not undergo any temperature extremes (do not place on ice / do not heat). An abstinence period of 2 -3 days is preferred since this reflects the abstinence period of a man when the couple is performing timed intercourse around the time of a woman's ovulation. Hormone tests It is common for a physician to obtain a blood test to check a man's reproductive hormones. Commonly obtained hormones include:
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In order for a man to have normal sperm production and function, his hormones must be in a proper balance. FSH and LH, which are made in the pituitary gland, regulate sperm production and testosterone production respectively. An abnormal prolactin level may be due to a benign growth of the pituitary gland which may suppress secretion of the other pituitary hormones. An elevated FSH is usually a sign of testicular failure and is commonly seen in men with very low sperm counts or no sperm at all (azoospermia).
Antisperm Antibodies Antibodies are proteins which are manufactured by the body when something foreign enters the system. During development, the body does not recognize sperm as part of the organism. Thus, if the body is exposed to a man's sperm, the body may form an "allergic" reaction towards the sperm and antibodies may be produced. Antisperm antibodies can affect fertility and in a small percentage of men it may be the only factor leading to infertility. Antisperm antibodies can bind to either the sperm head, midpiece, or tail. Antibody binding to the tail may affect sperm motility by impairing sperm tail movement. Antibody binding to the sperm head may interfere with the sperm head interaction with the egg. Antisperm antibodies are commonly seen in men who have undergone vasectomy. Other scenarios which may lead to antibody production include testicular injury or trauma, infections of the testicles or epididymis (orchitits / epididymitis), testicular torsion, and sexually transmitted diseases. Since the semen analysis may be normal in the presence of antisperm antibodies, the presence of antisperm antibodies needs to be suspected by the clinician and ordered in appropriate circumstances. Semen Culture Infection of the male reproductive tract may lead to impairment of sperm quality. When there is an infection of the male reproductive system, bacteria and/or white blood cells may be detected on the semen analysis. When these abnormal cells are detected in the semen, a semen culture may be performed to exclude the possibility of a semen infection. Semen is commonly tested for routine bacteria in addition to Chlamydia and Mycoplasma. White Blood Cells White blood cells (WBC's) in the semen may indicate either an infection or inflammation within the reproductive system. When examined by a routine microscope, WBC's and immature sperm appear similar. Both of these cells are larger and more round than sperm - thus, they are frequently referred to as "round cells". When these abnormal cells are detected, the laboratory should differentiate whether WBC's exist in the semen since further evaluation may be necessary. Most andrology laboratories will have separate assays and stains to differentiate WBC's from immature sperm. Strict Morphology When sperm are examined by routine microscopy, detailed assessment of sperm shape (morphology) can not be made. Since "normal" sperm shape has been correlated with high fertilization rates, an accurate assessment of sperm morphology is necessary. For a routine semen analysis, sperm are magnified 400 times by the microscope. The shape of these sperm is examined by the shadow cast by the microscope light. When an accurate assessment of sperm morphology is necessary, the sperm should be stained and examined under higher power (typically 900 - 1000 times). An assessment of sperm morphology should be performed in all cases of infertility. Sperm penetration assay (Hamster egg penetration) A semen analysis is not an assessment of fertility or sperm function. A semen analysis is only a measure of semen quality. When a measure of sperm function is necessary, one can obtain a sperm penetration assay (SPA). The SPA measures how well sperm can penetrate into hamster eggs that have been stripped of their outer coating. Normal sperm should penetrate the hamster eggs and the sperm DNA should decondense (unwind). This test is commonly performed if the semen analysis is relatively normal but the couple is having difficulty conceiving. It may also be performed in patients with a poor morphology to determine whether or not the sperm shape is interfering with sperm penetrating into | |||||||||||
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