Semen Analysis – Everything You Need To Know
Semen Analysis is a laboratory test that is performed on a fresh semen sample to determine male fertility. Semen, also known as seminal fluid, is a biologically cloudy white fluid that is produced by the male reproductive system during ejaculation. It is composed of sperms produced in the testes; as well as some other vital nutrients such as amino acids, sugars and certain enzymes that are produced and secreted by prostate gland and seminal vesicles. The bulbourethral glands secretes mucus to aid in the motility of the sperms.
The aim of semen analysis is to evaluate the semen sample on the basis of certain characteristics of sperms (such as shape, number and motility) under electronic microscope.
Comprehensive semen analysis serves following purposes:
- Determination or investigation of the primary cause of male infertility
- After vasectomy, to confirm the success of the procedure
The test is ordered by a physician or an andrologist and is carried out in a diagnostic laboratory. A cytologist or histopathologist examines the slides of semen sample to look for the specific characteristics of sperms as mentioned earlier. The other chemical parameters are measured on another specialized device.
Components Of Semen Analysis
The report of semen analysis covers certain specific features and aspects of the semen sample: These are as follows. The reference values of an adequate semen sample as per the recommendations of World Health Organization are also mentioned.
For an adequate sample:
- The total volume of semen ejaculated should be greater than 1.5 ml
- The sperm count (defined as the number of sperms per milliliter of the ejaculated semen) should be ≥15 Million/ml.
- The total sperm count refers to total number of sperms in a semen ejaculate. It should be ≥39 million.
- The sperm motility is another important parameter which is defined as the number of sperms that are capable of swimming/moving in the forward direction. It is expressed as a percentage and the normal value should be ≥40%.
- The sperm vitality is the percentage of live sperms in the sample. It should be ≥58%.
- The Morphology or shape of sperms is recorded as a percentage of normally shaped sperms compared to abnormally shaped ones. Experts believe that ≥4% sperms should have a normal morphology.
- Number of inflammatory white blood cells should be <1 million/ml of the semen ejaculate. Abnormally high concentration of inflammatory cells is suggestive of an active infection of the male reproductive tract.
- The pH of semen is a measure of acidity or alkalinity of sample and should be ideally on a mild alkaline side (reference value ≥7.2).
Sperm Morphology And Semen Sample
The shape of sperms is one of the essential factors that determines male fertility. If there are abnormalities in the head and tail of sperms, their movement is adversely affected which may lead to problems in fertilizing an egg. Normal sperm shape is associated with a higher male fertility.
Sperm antibodies are formed in a small proportion of men facing infertility issues. These are formed due to an immune mechanism. The phenomenon is especially common after vasectomy. These antibodies can negatively affect fertility by binding to the sperms, causing them to aggregate in an abnormal fashion. Also such sperms cannot swim efficiently in the female reproductive tract, or penetrate the egg. Some specialized laboratories have the expertise of measuring sperm antibodies in the semen sample.
In certain cases, a urine sample is also requested in order to rule out retrograde ejaculation of semen, a condition in which sperms are ejaculated back into the urinary bladder.
Interpretation Of Results
A normal semen analysis report does not guarantee fertility; but the inferences drawn from analysis can help in determining the possibility of conception. Reference ranges are usually mentioned alongside the patient values. The physician correlates these values with other useful clinical information like the frequency of sex between the couple, the duration for which couple is trying to conceive as well as the age and fertility status of the female partner.
1. Tepper, G., Rabbani, R., Yousefzadeh, M., & Prince, D. (2013). Quantitative assessment of retrograde ejaculation using semen analysis, comparison with a standardized qualitative questionnaire, and investigating the impact of rhBMP-2. Spine, 38(10), 841-845.
2. Soler, C., García-Molina, A., Sancho, M., Contell, J., Núñez, M., & Cooper, T. G. (2014). A new technique for analysis of human sperm morphology in unstained cells from raw semen. Reproduction, Fertility and Development.