The post-coital test (PCT) was designed as a rough guide to the state of the sperm which has the advantage of giving an on-the-spot result without needing recourse to a specialised laboratory or inconveniencing the patient.
The PCT is performed from 2 to 10 hours after normal intercourse during the 2-3 days immediately preceding ovulation when the cervical mucous is maximal. Outside of these days, a hostile cervical mucous will almost invariably give a false result. Mucous is drawn out from the cervix, placed on a microscope slide and examined under a microscope for the presence and movement of sperm. The result of the PCT is only really useful when positive i.e. the presence of more than 10 motile sperm per microscopic low power field is reassuring that intercourse is successfully depositing motile sperm in a receptive cervical mucous. A complete absence of sperm could indicate a faulty coital technique, an absence of sperm in the ejaculate or a hostile cervical mucous whereas the presence of non-motile sperm could indicate a hostile cervical mucous or non-motile sperm in the ejaculate.
Many units no longer apply the PCT as a routine examination due to its limited yield of useful information and it certainly must not replace a laboratory semen examination.
Amit Shah, Anil Gudi and Prof Homburg