This is simply the visual inspection and measurement of the sample. Firstly, the volume is measured and is typically between 1.5 – 5.0 ml. Next is the appearance of the sample. It should be white, maybe slightly off white and translucent, that is, you cannot see through it but it allows light to pass through.
Immediately after ejaculation the semen is a viscous, sticky semi-liquid which is quite difficult for the sperm to swim through. After about 10 minutes the semen undergoes a process that biochemically resembles blood clotting, except in reverse, and the semen becomes a free flowing liquid. This process is called liquefaction and is usually reported in the analysis as being complete or incomplete. Incomplete liquefaction is not necessarily a cause of infertility, but like an abnormal sample volume, it may give an indication to the functioning of accessary sex organs such as the seminal vesicles or prostate. The pH of the sample is measured and should be slightly alkaline at pH 7.2 or greater. An acidic sample with pH less than this is likely to indicate problems related to the seminal vesicles.