Hyperviscous semen is characterised by a thick, congealed appearance and remain in clumps when poured.

The coagulation and subsequent liquefaction of semen and its physiological significance is not clear. Hyperviscosity or delayed liquefaction is not always associated with infertility, since it is claimed that the spermatozoa are tangled in the fibrous or mucoid mass in the semen and are preventing the movement of sperm through the female genital tract. also it causes difficulties in ART assisted reproductive technique, when there is need of numbers of quality spermatozoa because hyperviscous semen is always difficult to manipulate in vitro and may not allow proper separation of quality spermatozoa an its number.

The Postcoital test help to evaluate male infertility factor in investigation.