Semen analysis and male infertility

What it is

Infertility is the inability of a sexually active, non-contracepting couple to achieve pregnancy in one year. Semen analysis is the initial male investigation, and the key laboratory assessment of the male partner of an infertile couple. The standard semen analysis gives the semen volume and pH, and microscopy for sperm concentration, count, motility and morphology, for debris and agglutination, for the leukocyte count, and for immature germ cells. For the couple it is the male half of the investigation, with a post-coital test done 2 to 12 hrs after intercourse to assess the number and mobility of the sperms that enter the cervical canal.

How it is diagnosed

The sample is collected after two to seven days of ejaculatory abstinence, and if possible by masturbation at the doctor's office; if that is not possible it may be collected at home and delivered to the laboratory within an hour of collection, while one source instead has the analysis performed within 2 hours of sample collection. Because sperm concentrations vary markedly between samples, at least two separate samples are collected: at least one week apart in one source, and at 12-week intervals in another. The analysis is done by standardized methods, preferably those described in the WHO Laboratory Manual for the Examination and Processing of Human Semen. A second list is stricter: the sample is collected after avoiding intercourse for 3 days, in a sterile container, and in the lab and not at home. The test is repeated if it is abnormal, again after 2 to 7 days of abstinence.

The reference values differ from one source to another. One gives lower reference limits of a volume of 1.5 ml, pH 7.2, sperm concentration 15 million per ml, total sperm number 39 million, total motility 40%, progressive or forward motility 32%, and normal morphology 4%. Another gives a volume of 2 to 5 ml, a count above 15 million per ml, motility above 32% progressive, morphology above 4% normal, liquefaction time within 30 min, and WBC below 1 million per ml. A third gives normal morphology above 30%, motility above 50% progressive at 1 hr, count above 20 million per ml, WBC below 1 million per ml, volume 2 to 5 ml, and liquefaction time within 30 minutes.

The abnormal findings have names of their own: oligospermia or oligozoospermia, a fall in the number of spermatozoa in semen; hypospermia, a fall in seminal volume; azoospermia, absence of sperm cells in semen; aspermia, complete lack of semen; teratospermia, a rise in sperm with abnormal morphology; asthenozoospermia, a fall in sperm motility; necrozoospermia, when all ejaculated sperm are dead; and leucospermia, a rise in white blood cells in semen.

Hormone analysis is indicated only in azoospermia or severe oligospermia, and it means prolactin and testosterone; sex hormone binding globulin and TSH are named with them, and imaging means a scrotal ultrasound for varicocele or obstruction. In azoospermia of normal volume, a low FSH and LH, in 2%, is pre-testicular; a normal FSH and LH, in 60%, leads to a testis biopsy, which tells testicular failure from obstructive azoospermia; and a high FSH and LH, in 40%, is testicular failure. Read the other way: a low serum testosterone with a high FSH and LH is gonadal failure, and karyotyping follows, or the cause is chemotherapy or radiation; a low testosterone with a low FSH and LH is hypogonadotropic hypogonadism; and a normal testosterone, FSH and LH points to obstruction, absence of the vas deferens or retrograde ejaculation, so a trans-rectal US is done. Azoospermia with a low volume, an acidic pH and absent fructose means an ejaculatory duct obstruction or a bilaterally absent vas deferens, told apart again by trans-rectal US. An infertile male with a low FSH, a low testosterone, no sperms in the semen, red-green colour blindness and anosmia has Kallman syndrome. The karyotype is what looks for aneuploidy, y chromosome microdeletion, CF mutation, kallmann and the androgen receptor.