The presence of spermatozoa in a urine test (spermaturia) is useful for the diagnosis of retrograde ejaculation in men with fertility problems.
Spermatozoa may be occasionally found in the urine of both men and women for the following reasons:
Laboratory protocols may differ reporting or not reporting the presence of spermatozoa in a urine specimen. Some labs do not report its presence because the clinical significance is not clear and to avoid possible legal consequences. Other labs support the clinical significance and the minimal possibility of legal consequences and they report it in any situation.
The test is performed in case of male infertility because it may help in the diagnosis of retrograde ejaculation.
Retrograde ejaculation occurs when semen travels backwards into the bladder instead of through the urethra during orgasm. Therefore, semen exits the body in the urine instead of being ejaculated.
To study the presence of spermatozoa in the urine, it is necessary to obtain previously the urinary sediment.
For this matter, the urine sample should be placed at rest for some hours waiting for the different elements of the urine (white and red blood cells, crystals, spermatozoa, etc.) precipitate to the bottom. As this process is very slow, the urine is centrifuged for about 5 minutes at 1500 or 2000 revolutions per second to obtain a sample of the sediment in less time.
Spermatozoa are easily identified in the urine sediment by their oval head that is somewhat teardrop shaped, and a long tail. Urine is toxic to spermatozoa; therefore, it is unusual that they exhibit the motility observed when examining a semen specimen.
The presence of a few spermatozoa in the urine usually has no clinical meaning.
The clinical significance of spermatozoa in a urine sample is limited to situations of male infertility and retrograde ejaculation in which the sperm is released into the bladder instead of into the urethra. In case of performing the test to detect a possible retrograde ejaculation it is better to collect the urine after ejaculation.
Besides, spermatozoa in urine may be seen in the presence of prostatic disease.
Elevated amounts of spermatozoa in the urine sample may cause a false positive in the protein urine test.