Evaluating Male Fertility
Many advances have been made in our ability to diagnose and treat fertility problems. Getting a complete and accurate diagnosis is essential to finding the best treatment or course of therapy. The andrology laboratory offers several diagnostic tests that can aid this treatment process, including semen analysis, sperm penetration assay, and an anti-sperm antibody test.
Acrosome Stimulation Test
The acrosome cap is a structure in the sperm head that surrounds the upper 40–60% of the sperm nucleus. The acrosome must function right for the sperm to penetrate the egg coating or zona pellucida. After the acrosome reaction, the sperm reveals binding sites that it needs for fusion to the egg. The acrosome stimulation test (which uses a double-detection system) identifies sperm that have acrosome reacted normally to artificial stimulation.
Anti-Sperm Antibody Test
In males, barriers exist to hide sperm from the body’s immune system. This is to keep the body from identifying the sperm as foreign, classifying it as dangerous, and producing a defense against it. When these barriers break down, the body produces anti-sperm antibodies. If these antibodies attach themselves to sperm, they cause damage to the sperm’s ability to move and/or agglutinate (clump with other cells).
Females may also produce anti-sperm antibodies. We can test for antibodies by evaluating seminal fluid, semen, and the serum from the woman. The anti-sperm antibody evaluation should be done if:
- In prepping for a vasectomy reversal, sperm motility is low.
- There is an increase of agglutination.
- Sperm function is in question.
Females should be evaluated if a sperm cervical mucus interaction assay test suggests a problem.
Cervical Mucus Interaction
This test will help determine the ability of sperm to penetrate ovulatory mucus. Ovulatory cervical mucus, along with the patient’s sperm and other fertile donor sperm, are placed side-by-side on a glass slide and covered. The motility of sperm that have penetrated the mucus is recorded at 30-minute intervals. If the donor sample performs better than the patient’s sperm, there may be male factor infertility. If both sperm samples do not perform well, the cervical mucus may be responding in a hostile way to the sperm.
Hamster Egg Penetration Test (Sperm Penetration Assay)
The hamster egg penetration test (HEPT) (also known as the sperm penetration assay) is the most accurate test in predicting the ability of the sperm to fertilize. It can also predict the ability of laboratory techniques to improve sperm fertilizing ability. The sperm samples are evaluated in a similar way as sperm in in-vitro fertilization (IVF), except that the eggs are obtained from a hamster and chemically treated to allow normal human sperm to penetrate them.
The prepared sperm are incubated with 15 to 20 chemically treated eggs. If the sperm is functioning, it can complete the first steps of fertilization, including the penetration of the egg, but nothing happens beyond that point. The penetrated eggs are counted and a percentage is calculated.
If fewer than 50% of the eggs are penetrated, the sperm has a decreased ability to fertilize. A percentage higher than 50% shows that the sperm should have the ability to fertilize.
If no sperm are found in the semen or if the count is extremely low, we may use a blood sample to evaluate hormone levels (FSH, LH, free testosterone, and total testosterone and prolactin). Clues from these tests may lead to possible causes and the best therapies.
Kruger or “Strict Criteria” Morphology
The term strict criteria morphology analysis refers to a specific technique that evaluates the shape of the sperm. The sperm morphology (shape) can predict the ability of the sperm to fertilize when combined with other fertility treatments. The test includes a very careful evaluation of the sperm head, tail, mid-piece, and tail attachment.
Hypoosomatic Solution Assay
The hypoosomatic solution assay tests a sperm’s viability/function. This test specifically examines the sperm’s plasma membrane and its ability to function, which may reveal its fertility. First we examine the seminal fluid’s consistency and the sperm’s motility. It is normal for the seminal fluid to have a small number of white blood cells, but a larger number of these cells may be an infection or prostatitis (inflammation of the prostate). If the white blood cell count is higher, we may take a semen culture, and a diagnosis and treatment for the problem may be found.
Five to 10% of fertility problems among couples are caused by irregularities in the cervix and its secretions. In order for sperm to successfully move through the cervix, the sperm must be able to penetrate the mucus. The lower cervix helps store sperm and releases it into the upper tract of the cervix before it enters the uterus.
The physical and chemical properties of cervical mucus vary with changes in the menstrual cycle. These changes affect the pH, viscosity, volume, cell content, and spinnbarkheit (measurement of stretch ability) in the cervical mucus making it more receptive to sperm penetration just before to ovulation.
We may recommend a retrograde semen analysis for patients with a low sperm count (from the initial semen analysis). Retrograde ejaculation is the ejaculation of sperm into the bladder. Urine released following sexual activity will contain sperm in men who have retrograde ejaculation.
Many retrograde ejaculation patients will have had prior surgery or a medical condition that predisposes them to retrograde ejaculation. These predisposing factors include testicular cancer surgery (RPLND), transurethral surgery of the prostate, or childhood bladder surgery. Medical conditions, such as diabetes, MS, or spinal cord injury, may also predispose an individual to retrograde ejaculation.
Semen analysis is the most efficient and inexpensive way to study male fertility. It is usually the starting point for a male infertility evaluation. It includes a study of sperm concentration, a motile sperm count (mobility), and study of sperm morphology (shape).
Lower sperm concentration and sperm motility affect the motile sperm count, which is a measurement of the sperm concentration that moves to the egg site to fertilize the egg. Sperm morphology is important as well because it reflects the ability of the sperm to fertilize an egg.
A normal semen sample may made of 35% normal correctly shaped sperm and the other 65% abnormally shaped or abnormal sperm. A smaller percentage of normal sperm could be a cause of reduced fertility.
A semen culture may be created when there is an increased number of white blood cells in the semen sample or the referring physician requests it. The semen sample is cultured for a bacterial growth. Samples showing growth are sent to another lab for identification of the bacteria and what antibiotics can kill the bacteria.
You can request more information on the presence of white blood cells in semen by contacting us.
Sperm Aneuploidy by FISH
FISH (fluorescent in-situ hybridization) allows us to identify and count chromosomes as well as any defects in chromosomes, such as chromosome translocations. By analyzing sperm with FISH prior to an IVF cycle or artificial insemination procedure, we can better counsel our patients as to the possible risks of an infertility treatment.
Sperm Chromatin Integrity Test (SCIT)
SCIT assesses chromatin integrity and DNA strand breaks, which have been shown to relate to embryo quality. DNA breaks are normally found during chromatin remodeling; however, this damage is repaired during the late stages of spermatogenesis. If the damage is not repaired however, the sperm DNA breaks may affect fertilization ability and embryo quality.
The SCIT sample is divided into two portions. One fraction will be used to evaluate DNA damage in the fresh sample, and the second portion will be tested by density gradient centrifugation. Then DNA damage will be analyzed in the final preparation.
The length of time sperm are able to remain functional after ejaculation could be a problem. The sperm longevity test can check the functionality of the sperm after it has been washed free from the seminal plasma and stored in a solution.
Transmission Electron Microscopy
To diagnose many sperm defects, we use transmission electron microscopy. The electron microscope uses very thin sections of sperm in a special plastic so that we can look at the sperm’s sub-cellular components highly magnified. This includes the sperm DNA acrosome, tail structure, and membrane structure.
Varicoceles are swollen veins in the scrotum. They are found in fertile as well as infertile men and are extremely common, but since they occur more in infertile men, they could harm fertility. Varicoceles are often found when there are fewer normal sperm and more tapered or abnormal sperm. It also seems to be associated with lower sperm concentration and motility. Like other forms of infertility, varicoceles is not associated with complete sterility, but with reduced fertility.
If the results of a semen analysis look like semen found in males with varicoceles, you may be referred to a urologist. The urologist will evaluate if you have a varicocele (usually directly above the testicle) and determine the best treatment. There may be no need for treatment, however, depending upon how much the varicocele may be affecting the patient or the plans of the couple to have more children. A surgical procedure called a varicocelectomy may be performed (on an outpatient basis) to correct the problem.
If no sperm are found in the seminal fluid, an evaluation of fructose will be performed. If no fructose is found, there may be a blockage of the vas deferens, which secretes fructose and carriers the sperm from the epididymis to the prostate gland.
X-Y Sperm Identification by FISH
Identifying the number of X or Y chromosome with sperm in an ejaculate can be a helpful diagnostic tool. We can evaluate very accurately by directly counting the number of sperm carrying either the X chromosome (those sperm that would result in a female child) or the Y chromosome (those sperm that would result in a male child).