Fern Test - Amniotic Fluid Crystallization Test
Back to Home Page
Specimen: Vaginal swab obtained from the
posterior vaginal pool.
- avoid the use of any lubricants or antiseptics
- use a sterile swab and do not touch the mucus plug
- prepare a thin smear on a glass microscope slide by spreading evenly.
|Positive Fern Test- note crystal formations||Negative Fern test- no "fern-like" cytstals|
Interfering Substances/ limitations:
If present, blood, urine or cervical mucus can result in a false positive finding.
False negative findings can result from prolonged rupture of membranes (>24 hr).
Images courtesy of University of Texas Medical Branch- POCT team. Used with permission.