Sperm Trial Wash

Choosing the appropriate wash

The trial wash or sperm survival test is a reasoned approach to find the appropriate method of wash for your sperm. Each individual's sperm will respond differently to the various sperm washing methods. During a trial wash, your sperm specimen is divided and washed using four different methods; (1) the swim-up, (2) the two-layer colloid, (3) TYB or Test-Yolk Buffer, and (4) a wash incorporating the motility stimulant pentoxifylline. The number of sperm cells recovered after each of the four washes is calculated and compared. Important parameters such as the percent motility, the percent progressive, and the percent sperm hyperactivation are analyzed by means of a computerized, automated sperm analyzer.

The sperm survival test (SST) indices for the four washes provide information on the potential fertility of the sperm. Finally, sperm taken from each of the four sperm washes are stressed at 40 ^o C (a high temperature for sperm) and the percentages of sperm surviving the treatments are reported. An optional second semen collection may be requested from you to find out if a second specimen will help to increase the sperm count or concentration for treatment procedures such as artificial insemination or in vitro fertilization (IVF).

For artificial insemination, the physician would like to have five million or more motile sperm cells after sperm washing, although pregnancies have resulted from lower sperm counts. For IVF without micromanipulation, we would like to recover greater than 500,000 motile sperm demonstrating about 5% hyperactivation and 75% or more of the sperm surviving the heat stress. Sperm of some patients do not respond favorably to stimulants such as pentoxifylline. The trial wash helps to reveal subtle sperm sensitivities before they are used on the actual day of insemination. The higher the percentage of sperm with hyperactive motility, the better the quality of the sperm specimen. Sperm showing 10% or higher percentages of hyperactivation are correlated to a higher fertilizing capacity.

Another important change that sperm must undergo before they can fertilize eggs is a process called capacitation. Capacitation generally peaks several hours after washing away seminal plasma components from the human sperm. Hence, in the trial wash, observation of the sperm cells several hours after washing helps to show which wash procedure maximizes the fertility potential of your sperm. It has been reported that fertile sperm can survive high temperature stress and it is expected that about 75% or more of the sperm will survive the stress. Sperm surviving the high temperature stress have been predictive of pregnancy after assisted reproductive techniques. Since semen specimens may vary in performance on different occasions, sometimes it is necessary to repeat the testing at another time.