Fern test

Common card · No. 474302

The fern test is a medical laboratory test used in obstetrics and gynecology. The name refers to the detection of a characteristic "fern like" pattern of vaginal secretions when a specimen is allowed to dry on a glass slide and is viewed under a low-power microscope. The fern test is most commonly used to provide evidence of the presence of amniotic fluid and is used in obstetrics to detect preterm premature rupture of membranes and/or the onset of labor. It also may provide indirect evidence of ovulation and fertility, although it does not predict the time of ovulation. Ferning was first described in the field of gynecology in 1945 by Georgios Papanikolaou, inventor of the Pap smear, as a test for ovulation during a normal menstrual cycle. When high levels of estrogen are present, such as just before ovulation (or during pregnancy), the cervical mucus forms fern-like patterns due to crystallization of sodium chloride on mucus fibers. This pattern is known as arborization or 'ferning'...

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