Laboratory:
Point of Care
Referral Laboratory:
MiChart Code:
Fern Test, Point of Care
Soft Order Code:
PFERN
Synonyms:
Onsite Collection (Michigan Medicine Hospitals Only):
1. A sterile speculum is placed into the vagina. A lubricant or antiseptic should not be used as these substances will affect ferning. 2. Using a sterile cotton swab, obtain sample of vaginal secretions from the posterior vagina where fluid has pooled. Do not touch the mucus plug on cervix.
Reference Range:
*Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Negative
Test Usage:
Performed by authorized providers in the point of care. Used to assess for premature amniotic fluid leakage: i.e. PROM (Premature Rupture of Membranes) or PPROM (Preterm Premature Rupture of Membranes).
Test Limitations:
•Cellar debris and blood in the sample may inhibit crystallization of amniotic fluid, and cause a false negative. •"Ferning" is not specific for amniotic fluid. Other fluids (e.g., blood cervical mucus, semen and some urine specimens) when dried can also yield microscopic crystallizations in a "fern" pattern, and cause false positives. •Prolonged rupture of membranes (greater than 24 hours) or slow, minimal leaks can yield false negative results.
Test Methodology:
Provider performed microscopy. The fern test is based on the ability of amniotic fluid to form a microscopic crystalline pattern that resembles fern leaves when the fluid air dries on a glass slide.
Additional Information:
For more test specific information, please refer to the test procedure found on the Michigan Medicine POC website: https://www.pathology.med.umich.edu/point-of-care
LOINC:
Q0114
CPT Code:
pH (72269-4), Ferning (54452-8)
Rejection Criteria:
If lubricants and antiseptics are used during the collection of the sample, the sample is to be rejected.
Test ID:
5715