Fructose: Fructose is the sugar present in the seminal fluid. It functions as an energy source for the sperm and is produced in the seminal vesicle. Absence of fructose suggests an obstruction in the path of the sperm from the testicles to the penis.
Leukocyte concentration: Leukocytes are white blood cells, and their presence suggests an infection, often of the prostate gland. This is reported as the number of white cells per 100 sperm present.
Morphology: This is the microscopic assessment of the appearance of the sperm. There are two techniques for evaluating morphology. The standard technique is done much more superficially and most laboratories use 60 percent normal sperm as their cut-off point for a normal semen analysis. The second technique uses stricter criteria. With this technique, the sperm are much more critically assessed, and a sperm must be perfectly normal to be so considered. Under these criteria, more than 14 percent normal-appearing sperm is outstanding, and more than four percent is probably normal. The use of the strict criteria for evaluating morphology is validated by the good correlation between normal appearance by these criteria and the fertilizing capacity of a sperm. Most labs specializing in semen analyses will use the strict criteria.
Total motile normal sperm (also known as TMNS): This is the bottom line of the semen analysis. This is the number of sperm that are normal by strict criteria and possess rapid progressive motility. In other words, this is how many sperm in the sample are capable of fertilizing an egg. The TMNS provides the physician with a number that he or she can use to determine which treatment alternatives will offer a couple an acceptable chance of conception.
Sperm penetration assay: A test in which sperm are incubated with specially prepared hamster eggs (actual fertilization cannot occur). The ability of the sperm to bind to the eggs and penetrate them is measured. The results of this test correlate moderately well with the ability to penetrate a human egg: If there is good penetration in this assay, there is a very good chance the sperm are capable of penetrating a human egg.
Sperm antibody tests: These tests check for the production of antibodies by either the male or female. Antibodies are substances that can immobilize or even kill the sperm before the sperm can reach the egg. In order to detect antibodies, a tube of blood is drawn from the woman and incubated with a sperm sample in the laboratory and examined microscopically.
Mannose test, acrosome reaction test: Before a sperm can attach to and fertilize an egg, it must undergo a process known as capacitation. Capacitation involves changes in the membrane of the head of the sperm that are necessary to allow attachment to, and penetration of, the egg. These tests measure the ability of the sperm to undergo capacitation and allow identification of sperm that may not be able to fertilize an egg in spite of an otherwise normal semen analysis. These tests can be particularly useful in cases of unexplained infertility or prior to an ART procedure. These are also known as sperm function tests (SFTs).
Sperm washing or Percoll gradient: Techniques used to isolate the healthiest and most motile sperm. A semen sample is subjected to one of these procedures prior to, for example, inseminations.
Testicular biopsy: A technique in which a small piece of the testicle(s) is surgically removed and microscopically evaluated. The value of this procedure in terms of suggesting ways to improve the sperm count is questionable at best. With the availability of microinsemination techniques such as ICSI (intracytoplasmic sperm injection), a testicular biopsy may be worthwhile in that if it demonstrates the presence of even a few very immature sperm, these can now be used to achieve fertilization and pregnancies.
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