Monday, 5 November, 2007
Antisperm Antibody Test
Antisperm antibodies (anti-spermatozoa antibodies, sperm antibodies) in the form of autoantibodies in male and alloantibodies in female patients directed against sperm antigens may prevent fertilization of the oocyte into the female genital tract and are therefore one of the major reasons for an immunologically induced infertility. Fertility disorders of unknown etiology of male as well as female patients result to a considerably amount (up to 20%) from antisperm antibodies.
An antisperm antibody test looks for special proteins (antibodies) that fight against a man's sperm in blood, vaginal fluids, or semen. The test uses a sample of sperm and adds a substance that binds only to affected sperm. Semen can cause an immune system response in either the man's or woman's body. The antibodies can damage or kill sperm. If a high number of sperm antibodies come into contact with a man's sperm, it may be hard for the sperm to fertilize an egg. The couple has a hard time becoming pregnant. This is called immunologic infertility.
A man can make sperm antibodies when his sperm comes into contact with his immune system. This can happen when the testicles are injured or after surgeries (such as a biopsy or vasectomy) or after a prostate gland infection. The testicles normally keep the sperm away from the rest of the body and the immune system. A woman can have an allergic reaction to her partner's semen and make sperm antibodies. This kind of immune response is not fully understood but may affect fertility. This is a rare cause of infertility.
The antisperm antibody test may be done if:a)A cause for infertility cannot be found. Experts disagree about the usefulness of the test because the result may not change the treatment. b)The results from another fertility test, such as the postcoital test, are not clear.
To do the test in women, a blood sample is taken from a vein in the arm. For men, a semen sample is collected after the blood samples are taken. You should not release your sperm (ejaculate) for 2 days before the test. It is important to not go longer than 5 days before the test without ejaculating.
The husband's sperm is tested for the presence of antisperm antibodies in the Direct ASAB Test. The husband should avoid ejaculation for a period of two to five days before his scheduled test. For the Indirect ASAB Test blood is drawn from the husband and/or wife and the serum is isolated from the blood. The serum is tested indirectly for the presence of antibodies to sperm by incubating it with donor sperm in the Indirect ASAB Test. If antisperm antibodies are present in the serum, they will attach to the donor sperm and cause a positive test result.
Your doctor may request the Immunobead Antisperm Antibody Test for a variety of reasons. These include a Semen Analysis which shows sperm agglutination (sticking together), a Post-Coital Test (PCT) which is abnormal, or unexplained infertility. This test is also a prerequisite for all IVF patients. Immunobeads are small beads that are treated with special proteins. If antibodies to sperm are present, these beads will attach to the sperm. One hundred motile (swimming) sperm are evaluated for bead attachment. For the male, if twenty or more of these sperm have beads attached to them (a result of 20% or greater), this is considered a positive test and indicates that antisperm antibodies may be present. For the female, a result greater than 10% is considered a positive test.
If the husband tests positive for ASAB, his semen specimen for IVF will be collected into a specimen cup containing a buffer solution that will minimize the effect of ASAB on the sperm. Normal IVF fertilization rates (fertilization of 50% or more of the mature eggs) are usually achieved with this treatment. When the female partner or both partners have tested positive for ASAB, or if the husband also has a compromised semen specimen (low count, low motility or low SPA), fertilization rates may be lower and your physician may suggest ICSI.