SPERM PENETRATION ASSAYS
There have been many attempts made to develop a Laboratory test that will accurately predict the ability of a human sperm to fertilize a human egg. Dr. Aitken and his group many years ago demonstrated a correlation between sperm movement characteristics and sperm fertilizing ability as evaluated by the zona pellucida-free hamster egg penetration test. In this test, the species specific barrier to penetration (not fertilization) is removed from the ova (eggs) of the hamster. These oocytes are then exposed to prepared sperm from the man being tested. There is some feeling that if a man's sperm are able to penetrate the hamster eggs in the laboratory, there is a higher likelihood that his sperm will ultimately be able to fertilize a human egg if so exposed. This test is not uniformly accepted, due to the high false negative (no penetration of the hamster egg, but wife gets pregnant anyway) rate and the sometimes seen false positive (penetrates the hamster egg but does not fertilize human eggs in vitro) rate of this test. Our experience has been that good performance in the hamster test can provide some limited reassurance of the likelihood that a man's sperm will be able to achieve fertilization if given the chance. If men fail the hamster test, we rely upon in vitro fertilization with ICSI. This protocol has provided us with excellent success rates in men whose sperm function remains questionable. It should be noted that most men that fail the hamster test, are able to achieve normal fertilization with ICSI. FOR A DETAILED EXPLANATION OF THE "HAMSTER TEST" CLICK HERE.
POSTCOITAL TESTING
The postcoital test (also known as the Huhner test or the Sims-Huhner test) is a valuable office test that should be carried out in selected patients early in their infertility evaluation. While this is a very popular and widely used test, there are no widely accepted normal values for the interpretation of this test. Simply, the postcoital (after intercourse) test evaluates the women's cervical mucus at the time of ovulation and how the mucus interacts with her husband's sperm as ovulation is about to occur. The couple is instructed to avoid sexual intercourse for two days prior to the exam. When evidence of impending ovulation is detected (LH testing, hormone blood tests, ultrasound, etc.) the couple is instructed to have intercourse and then present to the office 6 to 10 hours later (standard test). At this time, a small drop of mucus is painlessly removed from the endo(inner)cervix, and this drop is examined under the microscope. A favorable result would find many sperm in thin watery mucus, with good forward, active motion through the mucus. If the initial test is good, a second delayed exam (18-24 hours after intercourse) may be required if infertility persists. If the initial test is poor, a repeat exam carried out 2-3 hours after intercourse may be needed. The timing of the postcoital exam is very important. If carried out too soon after intercourse, sperm that appear normal at that time may later die, giving a false sense of security. Patients should assure that the test timing is appropriate, and that they are not just being squeezed in to a busy schedule at a convenient time. A normal test largely excludes the cervix as a contributor to any fertility problem.
SPERM WASHING AND FREEZING
Sperm "washing" techniques have been applied to treat a wide variety of sperm and semen disorders, as well as to prepare "normal" sperm for intrauterine insemination in the treatment of some female disorders. What is being "washed" in a sperm washing procedure are the various constituents of semen and the remainder of the ejaculate not deemed necessary to achieve fertilization of the egg. An ejaculate is not a sterile specimen and may contain both aerobic (oxygen dependednt) and anaerobic bacteria. In addition cellular debris from the vas deferens, the prostate, the seminal vesicles and thr urethra may be present. All of these components are "washed" from the specimen in the sperm wash procedure. <UNDER CONSTRUCTION><MORE TO FOLLOW>